# Fluent Bit changelog

> A fast log processor and forwarder.

- Vendor: Fluent
- Category: Developer Tools
- Official site: https://fluentbit.io
- Tracked by: What's New (https://whatsnew.fyi/product/fluent-bit)
- Harvested from: GitHub (fluent/fluent-bit)
- Entries below: 10 (newest first)

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

## Releases

### v5.1.0 — Fluent Bit 5.1.0

- Date: 2026-08-06
- Version: v5.1.0
- Original notes: https://github.com/fluent/fluent-bit/releases/tag/v5.1.0
- Permalink: https://whatsnew.fyi/product/fluent-bit/releases/v5.1.0

- **added** — Extract skills from memory
- **added** — Add in_gpu_metrics input plugin to handle NVIDIA GPU metrics via NVML
- **added** — Implement in_etw event tracing for Windows input plugin
- **added** — Add capability to adjust log level with error paths in in_node_exporter_metrics
- **added** — Add format=parquet,arrow with selectable page compression codecs to out_s3
- **added** — Handle input, output, filter, and processor plugin aliases
- **added** — Implement adaptive flushing in config engine
- **added** — Implement out_gcs Google Cloud Storage plugin
- **added** — Implement additional metrics (filesystem, EXT_* metrics, powersupplyclass) on node exporter metrics
- **added** — Support RA placeholders for dynamic creation of files in out_file
- **added** — Add per-container disk I/O metrics to in_podman_metrics
- **added** — Initial implementation to enable FIPS compliance
- **changed** — Enrich EventData key-value map if enabled in in_winevtlog
- **changed** — Upgrade cmetrics library to v2.2.0
- **changed** — Upgrade cfl library to v1.0.0
- **changed** — Reduce protobuf log allocation churn in opentelemetry
- **changed** — Re-architect workers support in downstream
- **changed** — Reduce protobuf decode allocation churn in in_opentelemetry
- **changed** — Handle DTLS protocol on out_syslog
- **changed** — Add coroutine-based event dispatch to downstream
- **changed** — Reload and watch certificates on Linux in OpenSSL TLS
- **fixed** — Return not found for invalid endpoint in in_opentelemetry
- **fixed** — Do not recycle a connection after peer close_notify in OpenSSL TLS
- **fixed** — Fix incorrectly detected C TLS existence in thread_storage
- **fixed** — Fix stale byte accounting when multiple frames share a buffer in in_forward
- **fixed** — Plug 2038 problem on timestamp in log_event_decoder time
- **fixed** — Plug unsupported shared port issue on Windows in http_server
- **fixed** — Handle byte order mark for non-ASCII environment of Windows correctly in tests
- **fixed** — Plug uninitialized member in network
- **fixed** — Avoid unbounded recursion in chunk cobj record iteration in mp
- **fixed** — Plug SEGV occurrence on enabling Use_Pod_Association in filter_kubernetes
- **fixed** — Fix the reported RSS ram in in_process_exporter_metrics
- **fixed** — Adjust consuming mechanism to improve throughput in in_lib

https://fluentbit.io/announcements/v5.1.0/

##### What's Changed
* workflows: bump docker/login-action from 4.3.0 to 4.4.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12055
* build: bump to v5.1 (dev) by @edsiper in https://github.com/fluent/fluent-bit/pull/12066
* skills: Extract skills from memory by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12068
* in_opentelemetry: return not found for invalid endpoint by @edsiper in https://github.com/fluent/fluent-bit/pull/12064
* workflows: bump actions/stale from 10.3.0 to 10.4.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12081
* workflows: bump github/codeql-action/upload-sarif from 4.36.3 to 4.37.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12074
* tls: openssl: don't recycle a connection after peer close_notify by @ku524 in https://github.com/fluent/fluent-bit/pull/12079
* in_winevtlog: Enrich EventData key-value map if enabled by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12082
* lib: cmetrics: upgrade to v2.2.0 by @edsiper in https://github.com/fluent/fluent-bit/pull/12083
* thread_storage: Fix incorrectly to detect C TLS existence by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12067
* in_forward: fix stale byte accounting when multiple frames share a buffer by @zshuang0316 in https://github.com/fluent/fluent-bit/pull/12049
* lib: cfl: upgrade to v1.0.0 by @edsiper in https://github.com/fluent/fluent-bit/pull/12084
* opentelemetry: reduce protobuf log allocation churn by @edsiper in https://github.com/fluent/fluent-bit/pull/12087
* in_gpu_metrics: Handle NVIDIA GPU metrics via NVML by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11720
* log_event_decoder: time: plug 2038 problem on timestamp by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11549
* in_etw: Implement event tracing for windows input plugin by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12072
* tests: runtime: plugins: Enable to build and run runtime testcases on windows by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12092
* lib: cmetrics: upgrade to v2.2.1 by @edsiper in https://github.com/fluent/fluent-bit/pull/12088
* in_opentelemetry: reduce protobuf decode allocation churn by @edsiper in https://github.com/fluent/fluent-bit/pull/12089
* in_node_exporter_metrics: Add a capability to adjust log level w/ error paths by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12057
* downstream: re-architect workers support by @edsiper in https://github.com/fluent/fluent-bit/pull/11775
* github: workflows: Enable runtime tests only for x64 Windows architecure by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12098
* http_server: plug unsupported shared port issue on windows by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12101
* workflows: bump softprops/action-gh-release from 3.0.1 to 3.0.2 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12099
* tests: runtime: Handle byte order mark for non-ASCII environment of Windows correctly by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12100
* network: Plug an unintialized member by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12102
* tests: runtime: out_tcp: Make more rigid accumutated assertions by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12104
* workflows: bump github/codeql-action/upload-sarif from 4.37.0 to 4.37.1 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12108
* github: workflows: Enable unit testing on 5.0 branch by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12122
* mp: avoid unbounded recursion in chunk cobj record iteration by @zshuang0316 in https://github.com/fluent/fluent-bit/pull/12126
* tests: link test binaries against shared library by @edsiper in https://github.com/fluent/fluent-bit/pull/12128
* out_s3: add format=parquet,arrow with selectable page compression codecs by @rituparnakhaund in https://github.

_[Truncated at 4000 characters — full notes: https://github.com/fluent/fluent-bit/releases/tag/v5.1.0]_

### v4.2.8 — Fluent Bit 4.2.8

- Date: 2026-08-04
- Version: v4.2.8
- Original notes: https://github.com/fluent/fluent-bit/releases/tag/v4.2.8
- Permalink: https://whatsnew.fyi/product/fluent-bit/releases/v4.2.8

- **changed** — Enrich EventData key-value map in in_winevtlog if enabled
- **fixed** — Fix payload parsing over-reads and null safety in out_stackdriver
- **fixed** — Handle empty map in out_kafka even if avro schema defines map type

https://fluentbit.io/announcements/v4.2.8/

##### What's Changed
* release: update to 4.2.8 by @github-actions[bot] in https://github.com/fluent/fluent-bit/pull/12075
* in_winevtlog: Enrich EventData key-value map if enabled [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12161
* out_stackdriver: fix payload parsing over-reads and null safety [Backport to 4.2] by @baizhenyu in https://github.com/fluent/fluent-bit/pull/12170
* avro: out_kakfa: handle empty map even if avro schema defines map type [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12209


**Full Changelog**: https://github.com/fluent/fluent-bit/compare/v4.2.7...v4.2.8

### v4.2.7 — Fluent Bit 4.2.7

- Date: 2026-07-09
- Version: v4.2.7
- Original notes: https://github.com/fluent/fluent-bit/releases/tag/v4.2.7
- Permalink: https://whatsnew.fyi/product/fluent-bit/releases/v4.2.7

- **changed** — Upgrade librdkafka to v2.15.0
- **fixed** — Validate PING is a msgpack array in check_ping for in_forward
- **fixed** — Align secure forward handshake and chunk ack with protocol spec in out_forward
- **fixed** — Read magic number endian-safely in streaming decompressor for gzip
- **fixed** — Fix 100% CPU hang and connection teardown use-after-free in in_forward
- **fixed** — Return Splunk HEC auth status codes in in_splunk

https://fluentbit.io/announcements/v4.2.7/

##### What's Changed
* release: update to 4.2.7 by @github-actions[bot] in https://github.com/fluent/fluent-bit/pull/12005
* releasse: Update version to v4.2.7 [4.2 branch] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12015
* github: workflows: Use semver and timestamp suffixes to distinguish branches [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12017
* lib: librdkafka: Upgrade to v2.15.0 [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12050
* in_forward: validate PING is a msgpack array in check_ping [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12051
* out_forward: align secure forward handshake and chunk ack with protocol spec [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12052
* gzip: read magic number endian-safely in streaming decompressor [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12056
* in_forward: fix 100% CPU hang and connection teardown use-after-free [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12053
* in_splunk: return Splunk HEC auth status codes [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12071


**Full Changelog**: https://github.com/fluent/fluent-bit/compare/v4.2.6...v4.2.7

### v5.0.9 — Fluent Bit 5.0.9

- Date: 2026-07-04
- Version: v5.0.9
- Original notes: https://github.com/fluent/fluent-bit/releases/tag/v5.0.9
- Permalink: https://whatsnew.fyi/product/fluent-bit/releases/v5.0.9

- **added** — Implement user-defined performance counters with PDH in in_windows_exporter_metrics
- **added** — Implement openssl trace in in_ebpf
- **changed** — Upgrade librdkafka to v2.15.0
- **changed** — Generate mostly monotonic event id for increasing traceability in in_ebpf
- **changed** — Align secure forward handshake and chunk ack with protocol spec in out_forward
- **changed** — Attach k8s metadata for internal logs in filter_kubernetes
- **changed** — Use semver and timestamp suffixes to distinguish branches in workflows
- **fixed** — Validate PING is a msgpack array in check_ping in in_forward
- **fixed** — Plug segmentation violation on in_tail
- **fixed** — Mitigate data loss on multiline in filter_write_tag and in_emitter
- **fixed** — Plug segmentation violation on not found error in out_cloudwatch_logs
- **fixed** — Fix multi-worker resource-metadata data race in out_stackdriver
- **fixed** — Fix payload parsing over-reads and null safety in out_stackdriver
- **fixed** — Skip FCOMMENT terminator in streaming decompressor in gzip
- **fixed** — Fix 100% CPU hang and connection teardown use-after-free in in_forward
- **fixed** — Fix int64_t line var in out_stackdriver and gzip endian-safe magic check
- **changed** — Return Splunk HEC auth status codes in in_splunk

https://fluentbit.io/announcements/v5.0.9/

##### What's Changed
* workflows: bump azure/setup-helm from 5.0.0 to 5.0.1 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/11997
* workflows: bump actions/setup-python from 6.2.0 to 6.3.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/11996
* workflows: bump actions/cache from 5.0.5 to 6.0.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/11995
* github: workflows: Use semver and timestamp suffixes to distinguish branches by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12016
* workflows: bump actions/cache/restore from 6.0.0 to 6.1.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12011
* workflows: bump crazy-max/ghaction-chocolatey from 4.0.0 to 4.1.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12012
* workflows: bump actions/cache/save from 6.0.0 to 6.1.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12013
* release: update to 5.0.9 by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12018
* in_windows_exporter_metrics: Implement user-defined performance counters w/ PDH by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12006
* tests: runtime: Try to address test hang by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12000
* workflows: bump docker/build-push-action from 7.2.0 to 7.3.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12031
* workflows: bump docker/setup-qemu-action from 4.1.0 to 4.2.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12030
* in_forward: validate PING is a msgpack array in check_ping by @saddamr3e in https://github.com/fluent/fluent-bit/pull/12034
* filter_kubernetes: Attach k8s metadata for internal logs by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11998
* in_ebpf: Implement openssl trace by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11793
* tests: runtime: Use more concrete matchers for assertions by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12014
* in_tail: Another attempt to plug segv on in tail by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12010
* filter_write_tag: in_emitter: Mitigate data loss on multiline by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12029
* workflows: bump docker/setup-buildx-action from 4.1.0 to 4.2.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12041
* workflows: bump docker/login-action from 4.2.0 to 4.3.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12040
* workflows: bump docker/metadata-action from 6.1.0 to 6.2.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12039
* workflows: bump github/codeql-action/upload-sarif from 4.36.2 to 4.36.3 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/12038
* out_cloudwatch_logs: Plug SEGV on not found error by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11983
* lib: librdkafka: Upgrade to v2.15.0 by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12028
* in_ebpf: Generate mostly monotonic event id for increasing traceability by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12002
* in_splunk: return Splunk HEC auth status codes by @lecaros in https://github.com/fluent/fluent-bit/pull/12043
* out_forward: align secure forward handshake and chunk ack with protocol spec by @edsiper in https://github.com/fluent/fluent-bit/pull/12037
* out_stackdriver: fix multi-worker resource-metadata data race (SIGSEGV) by @erain in https://github.com/fluent/fluent-bit/pull/12023
* out_stackdriver: fix payload parsing over-reads and null safety by @erain in https://github.com/fluent/fluent-bit/pull/12022
* codeowners: update @jeffluoo to @JeffLuoo by @JeffLuoo in https://github.com/fluent/fluent-bit/pull/11941
* gzip: skip FCOMMENT terminator in streaming decompressor by @saddamr3e in https://github.com/fluent/fluent-bit/pull/11969
* in_forward: fix 100% CPU han

_[Truncated at 4000 characters — full notes: https://github.com/fluent/fluent-bit/releases/tag/v5.0.9]_

### v4.2.6 — Fluent Bit 4.2.6

- Date: 2026-06-26
- Version: v4.2.6
- Original notes: https://github.com/fluent/fluent-bit/releases/tag/v4.2.6
- Permalink: https://whatsnew.fyi/product/fluent-bit/releases/v4.2.6

- **fixed** — Fix multiple memory leaks and potential corruption in out_stackdriver
- **fixed** — Harden token refresh parsing in oauth2
- **fixed** — Handle conversion rules of windows and IANA tzinfo in time_tz
- **added** — Add IANA time_zone support for native timestamps in parser
- **fixed** — Plug a regex literal crash
- **fixed** — Plug bitwise glitches on 32bit OSes in in_windows_exporter_metrics
- **fixed** — Use the correct maximum size of Cyrillic in unicode
- **fixed** — Process type and length of pong strictly in out_forward
- **changed** — Add file path to error messages in node_exporter_metrics
- **fixed** — Sanitize bulk action metadata in out_es and out_opensearch
- **fixed** — Plug file descriptor leaks on destroy in scheduler

https://fluentbit.io/announcements/v4.2.6/

##### What's Changed
* release: update to 4.2.6 by @github-actions[bot] in https://github.com/fluent/fluent-bit/pull/11907
* workflows: Windows docker insufficient disk space fix [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11906
* time: time_tz: Handle conversion rules of windows and IANA tzinfo [Back port to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11911
* out_stackdriver: fix multiple memory leaks and potential corruption [Backport to 4.2] by @baizhenyu in https://github.com/fluent/fluent-bit/pull/11916
* parser: Add IANA time_zone support for native timestamps [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11919
* oauth2: harden token refresh parsing [Backport to 4.2] by @baizhenyu in https://github.com/fluent/fluent-bit/pull/11923
* dockerfiles: windows: fixed VS Build Tools installation [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11920
* workflows: Windows Docker insufficient disk space fix (2nd attempt) [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11927
* out_stackdriver: backport codeowners change by @braydonk in https://github.com/fluent/fluent-bit/pull/11921
* github: workflows: Process unit tests on 4.2 branch [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11932
* github: workflows: Specify OS configs explicitly [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11935
* regex: Plug a regex literal crash [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11946
* in_windows_exporter_metrics: Plug bitwise glitches on 32bit oses [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11947
* unicode: Use the correct maximum size of Cyrillic [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11929
* out_forward: process type and length of pong strictly [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11949
* node_exporter_metrics: Add file path to error messages [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11992
* out_es/out_opensearch: sanitize bulk action metadata [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11993
* tests: runtime: Try to eliminate flakyness on CI load [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11994
* scheduler: Plug FD leaks on destroy [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/12001


**Full Changelog**: https://github.com/fluent/fluent-bit/compare/v4.2.5...v4.2.6

### v5.0.8 — Fluent Bit 5.0.8

- Date: 2026-06-24
- Version: v5.0.8
- Original notes: https://github.com/fluent/fluent-bit/releases/tag/v5.0.8
- Permalink: https://whatsnew.fyi/product/fluent-bit/releases/v5.0.8

- **added** — Implement sched trace in in_ebpf
- **fixed** — Plug bitwise glitches on 32bit OSes in in_windows_exporter_metrics
- **fixed** — Plug a regex literal crash
- **fixed** — Process type and length of pong strictly in out_forward
- **fixed** — Use the correct maximum size of Cyrillic in unicode
- **fixed** — Render unset AnyValue in OTLP JSON in opentelemetry
- **fixed** — Fix stale chunks handling on limits in storage
- **fixed** — Plug timer lifecycle glitches on progress check in in_tail
- **fixed** — Handle structured xml query as separated subscriptions in in_winevtlog
- **fixed** — Plug SEGV occurrences on cloudwatch logs in aws error_reporter
- **fixed** — Fix out-of-bounds read in unesc_ends_with_nl in in_tail
- **fixed** — Fix caller-owned parse failure cleanup in config_format
- **fixed** — Plug FD leaks on destroy in scheduler
- **fixed** — Handle loki tenant_id_key properly in out_loki
- **fixed** — Ensure escaping backslashes on cloudwatch API requests' body in out_cloudwatch_logs
- **fixed** — Fix ignore_active_older_files to re-check mtime on aged-out files in in_tail
- **fixed** — Catch auth errors on XML responses in aws
- **fixed** — Correctly handle successful Delete Blob responses in out_azure_blob
- **fixed** — Sanitize bulk action metadata in out_es and out_opensearch
- **fixed** — Fix JSON histogram bounds handling in opentelemetry
- **changed** — Upgrade cmetrics to v2.1.5

https://fluentbit.io/announcements/v5.0.8/

##### What's Changed
* release: update to 5.0.8 by @github-actions[bot] in https://github.com/fluent/fluent-bit/pull/11924
* github: workflows: Adjust permissions to make efficient package/integration tests by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11936
* github: workflows: Specify OS configs explicitly by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11934
* in_windows_exporter_metrics: Plug bitwise glitches on 32bit oses by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11940
* regex: Plug a regex literal crash by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11938
* out_forward: process type and length of pong strictly by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11945
* unicode: Use the correct maximum size of Cyrillic by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11928
* opentelemetry: render unset AnyValue in OTLP JSON by @edsiper in https://github.com/fluent/fluent-bit/pull/11943
* storage: fix stale chunks handling on limits by @edsiper in https://github.com/fluent/fluent-bit/pull/11632
* workflows: bump actions/checkout from 6.0.3 to 7.0.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/11965
* in_ebpf: Implement sched trace by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11743
* in_tail: Plug timer lifecycle glitches on progress check by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11956
* in_winevtlog: Handle structured xml query as separated subscriptions by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11957
* aws: error_reporter: Plug SEGV occurrences on cloudwatch logs by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11966
* in_tail: fix out-of-bounds read in unesc_ends_with_nl by @saddamr3e in https://github.com/fluent/fluent-bit/pull/11952
* config_format: fix caller-owned parse failure cleanup by @edsiper in https://github.com/fluent/fluent-bit/pull/11955
* workflows: bump softprops/action-gh-release from 3.0.0 to 3.0.1 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/11976
* workflows: bump github/codeql-action from 4.36.1 to 4.36.2 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/11975
* scheduler: Plug FD leaks on destroy by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11977
* dockefile: Install libxxhash0 on builder image by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11980
* workflows: bump aquasecurity/trivy-action from 0.35.0 to 0.36.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/11982
* workflows: bump reviewdog/action-hadolint from 1.50.5 to 1.51.0 by @dependabot[bot] in https://github.com/fluent/fluent-bit/pull/11981
* out_loki: Handle loki tenant_id_key properly by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11832
* out_cloudwatch_logs: Ensure escaping backslashes on cloudwatch API requests' body by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11933
* tests: runtime: Try to eliminate flakyness on CI load by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11984
* in_tail: fix ignore_active_older_files to re-check mtime on aged-out files by @zshuang0316 in https://github.com/fluent/fluent-bit/pull/11890
* aws: catch auth errors on XML responses by @antoniomrfranco in https://github.com/fluent/fluent-bit/pull/11891
* out_azure_blob: correctly handle successful Delete Blob responses by @Vaibhav-C-S in https://github.com/fluent/fluent-bit/pull/11925
* node_exporter_metrics: Add file path to error messages by @rossigee in https://github.com/fluent/fluent-bit/pull/11839
* out_es/out_opensearch: sanitize bulk action metadata by @edsiper in https://github.com/fluent/fluent-bit/pull/11967
* opentelemetry: fix JSON histogram bounds handling by @edsiper in https://github.com/fluent/fluent-bit/pull/11989
* lib: cmetrics: upgrade to v2.1.5 by @edsiper in https://github.com/fluent/fluent-bit/pull/11990

##### New Contributors
* @saddam

_[Truncated at 4000 characters — full notes: https://github.com/fluent/fluent-bit/releases/tag/v5.0.8]_

### v5.0.7 — Fluent Bit 5.0.7

- Date: 2026-06-06
- Version: v5.0.7
- Original notes: https://github.com/fluent/fluent-bit/releases/tag/v5.0.7
- Permalink: https://whatsnew.fyi/product/fluent-bit/releases/v5.0.7

- **fixed** — Serialize worker teardown in http_server to prevent race conditions
- **fixed** — Fix libevent crash on connection drop in http_server
- **added** — Support label and namespace mapping in out_chronicle
- **fixed** — Fix YAML variant cleanup on parser errors in config_format
- **fixed** — Handle int64 values correctly in avro
- **fixed** — Check map size before accessing first entry in in_elasticsearch
- **security** — Fix OOB reads in framed data parser in snappy
- **changed** — Add 100 MB decompression size limit to zstd
- **security** — Fix OOB read from hardcoded remaining length overhead in in_mqtt
- **security** — Reject parts with length < 4 and fix null-terminator OOB in in_collectd
- **security** — Validate array size before accessing message mode fields in in_forward
- **security** — Fix integer overflow in octet-counting length parser in in_syslog
- **fixed** — Fix multiple memory leaks and potential corruption in out_stackdriver
- **changed** — Handle conversion rules of windows and IANA tzinfo in time_tz
- **fixed** — Discard checksum corrupt chunks on startup in storage
- **added** — Add IANA time_zone support for native timestamps in parser
- **changed** — Increase PUT_RECORDS_PAYLOAD_SIZE to 10MB in out_kinesis_streams
- **added** — Support stdin plugin on windows in in_stdin
- **added** — Implement dns trace in in_ebpf
- **added** — Provide options for inactive chunks behavior in out_s3

https://fluentbit.io/announcements/v5.0.7/

##### What's Changed
* release: update to 5.0.7 by @github-actions[bot] in https://github.com/fluent/fluent-bit/pull/11834
* http_server: serialize worker teardown to prevent race conditions by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11845
* http_server: fix libevent crash on connection drop by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11843
* out_chronicle: Support label and namespace mapping by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11836
* tests: internal: fuzzers: avoid destroying active input fuzzer tasks by @edsiper in https://github.com/fluent/fluent-bit/pull/11850
* config_format: fix YAML variant cleanup on parser errors by @edsiper in https://github.com/fluent/fluent-bit/pull/11857
* avro: Handle int64 values correctly by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11883
* tests: runtime: Stabilize out_lib test case by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11888
* in_elasticsearch: check map size before accessing first entry by @TristanInSec in https://github.com/fluent/fluent-bit/pull/11856
* snappy: fix OOB reads in framed data parser by @TristanInSec in https://github.com/fluent/fluent-bit/pull/11855
* zstd: add 100 MB decompression size limit by @TristanInSec in https://github.com/fluent/fluent-bit/pull/11854
* in_mqtt: fix OOB read from hardcoded remaining length overhead by @TristanInSec in https://github.com/fluent/fluent-bit/pull/11853
* in_collectd: reject parts with length < 4 and fix null-terminator OOB by @TristanInSec in https://github.com/fluent/fluent-bit/pull/11849
* in_forward: validate array size before accessing message mode fields by @TristanInSec in https://github.com/fluent/fluent-bit/pull/11851
* in_syslog: fix integer overflow in octet-counting length parser by @TristanInSec in https://github.com/fluent/fluent-bit/pull/11852
* out_stackdriver: fix multiple memory leaks and potential corruption by @baizhenyu in https://github.com/fluent/fluent-bit/pull/11879
* CODEOWNERS: remove @braydonk and @jefferbrecht by @braydonk in https://github.com/fluent/fluent-bit/pull/11909
* time: time_tz: Handle conversion rules of windows and IANA tzinfo by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11903
* storage: discard checksum corrupt chunks on startup by @edsiper in https://github.com/fluent/fluent-bit/pull/11886
* parser: Add IANA time_zone support for native timestamps by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11913
* workflows: pin all actions to SHA by @patrick-stephens in https://github.com/fluent/fluent-bit/pull/11908
* out_kinesis_streams: increase PUT_RECORDS_PAYLOAD_SIZE to 10MB by @ShelbyZ in https://github.com/fluent/fluent-bit/pull/11848
* in_stdin: support stdin plugin on windows by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11821
* in_ebpf: Implement dns trace by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11735
* out_s3: Provide options for inactive chunks behavior by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11816
* oauth: out_http: add user-agent option for oauth by @rja5 in https://github.com/fluent/fluent-bit/pull/11830
* in_tail: fix offset_key value multiplied by 8 on Windows 64-bit by @zshuang0316 in https://github.com/fluent/fluent-bit/pull/11893
* http_client_http2: bracket IPv6 authority hosts by @edsiper in https://github.com/fluent/fluent-bit/pull/11922

##### New Contributors
* @TristanInSec made their first contribution in https://github.com/fluent/fluent-bit/pull/11856
* @rja5 made their first contribution in https://github.com/fluent/fluent-bit/pull/11830

**Full Changelog**: https://github.com/fluent/fluent-bit/compare/v5.0.6...v5.0.7

### v4.2.5 — Fluent Bit 4.2.5

- Date: 2026-06-03
- Version: v4.2.5
- Original notes: https://github.com/fluent/fluent-bit/releases/tag/v4.2.5
- Permalink: https://whatsnew.fyi/product/fluent-bit/releases/v4.2.5

- **added** — Add support for Ubuntu 26.04
- **added** — Add bash-style default value operator :- for environment variables
- **added** — Support label and namespace mapping in out_chronicle
- **fixed** — Replace raw read() with pipe abstraction in input_thread to fix crash
- **fixed** — Set up proper block size for aws compression arrow
- **fixed** — Handle bracketed IPv6 addresses in network
- **fixed** — Address wrong assignments of timezone at midnight in parser
- **fixed** — Fix issue with missing input alias in routing
- **fixed** — Plug tag keys failure in out_influxdb
- **fixed** — Fix integer divide-by-zero on Windows x64 in bytes_to_human_readable_size
- **fixed** — Do not recycle connections in filter_kubernetes fetch_pod_service_map
- **fixed** — Fix file append cleanup on failure in in_tail
- **fixed** — Destroy TLS session in filter_kubernetes to prevent SSL object leak
- **fixed** — Destroy upstream and TLS context on happy path exit in filter_kubernetes
- **fixed** — Ignore duplicate STOP in engine to prevent shutdown spin
- **fixed** — Use pre_run callback in in_dummy to fix crash path
- **removed** — Remove promoted known keys from out_logdna
- **fixed** — Fix build with OPENSSL_NO_ENGINE in crypto
- **fixed** — Plug SEGV on termination in out_azure_logs_ingestion
- **fixed** — Handle unpacker allocation failure in in_forward
- **fixed** — Handle int64 values correctly in avro

https://fluentbit.io/announcements/v4.2.5/

##### What's Changed
* release: update to 4.2.5 by @github-actions[bot] in https://github.com/fluent/fluent-bit/pull/11697
* packaging: add support for Ubuntu 26.04 (backport to 4.2) by @patrick-stephens in https://github.com/fluent/fluent-bit/pull/11803
* backport: env: add bash-style default value operator :- by @benjaminmueggenburg-serato in https://github.com/fluent/fluent-bit/pull/11806
* out_chronicle: Support label and namespace mapping [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11837
* input_thread: replace raw read() with pipe abstraction to fix crash [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11860
* aws: compression: arrow: Set up proper block size [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11861
* network: Handle braketed ipv6 addresses [backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11862
* parser: Address wrong assignments of timezone at midnight [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11863
* routing: fix issue with missing input alias [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11864
* out_influxdb: plug tag keys failure on out influxdb [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11865
* utils: fix integer divide-by-zero on Windows x64 in bytes_to_human_readable_size [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11866
* filter_kubernetes: don't recycle connections in fetch_pod_service_map [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11867
* in_tail: fix file append cleanup on failure [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11871
* filter_kubernetes: destroy TLS session to prevent SSL object leak [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11868
* filter_kubernetes: destroy upstream and TLS context on happy path exit [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11869
* engine: ignore duplicate STOP to prevent shutdown spin [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11870
* in_dummy: Use pre_run callback to fix crash path [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11872
* out_logdna: remove promoted known keys [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11873
* crypto: fix build with OPENSSL_NO_ENGINE [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11874
* out_azure_logs_ingestion: Plug SEGV on termination [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11875
* in_forward: handle unpacker allocation failure [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11881
* tests: runtime: wait for tail truncate output [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11882
* avro: Handle int64 values correctly [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11892
* mp: fixed count when empty data by @edsiper in https://github.com/fluent/fluent-bit/pull/11894
* in_collectd: reject parts with length < 4 and fix null-terminator OOB [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11896
* in_forward: validate array size before accessing message mode fields [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11897
* in_syslog: fix integer overflow in octet-counting length parser [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11898
* in_mqtt: fix OOB read from hardcoded remaining length overhead [Backport to 4.2] by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11899
* zstd: cap buffer at max instead of aborting on overshoot [Backport to 4.2] by @cosmo0920 in https

_[Truncated at 4000 characters — full notes: https://github.com/fluent/fluent-bit/releases/tag/v4.2.5]_

### v5.0.6 — Fluent Bit 5.0.6

- Date: 2026-05-21
- Version: v5.0.6
- Original notes: https://github.com/fluent/fluent-bit/releases/tag/v5.0.6
- Permalink: https://whatsnew.fyi/product/fluent-bit/releases/v5.0.6

- **added** — Add bash-style default value operator :- for environment variables
- **added** — Add support for Ubuntu 26.04 in packaging
- **added** — Add total limit size configuration for DLQ in storage
- **changed** — Upgrade cfl library to v0.7.1
- **changed** — Partition OTLP logs by resource in out_kafka
- **changed** — Harden listener and architecture for http_server
- **changed** — Spawn internal server in threaded mode for http_server
- **changed** — Omit SNI for IP literal hosts in TLS
- **fixed** — Fix general issues with sds_cat() usage
- **fixed** — Handle unpacker allocation failure in in_forward
- **fixed** — Prevent port binding failures in concurrent OTEL tests
- **fixed** — Ignore duplicate STOP messages to prevent shutdown spin in engine
- **fixed** — Plug segmentation fault on termination in out_azure_logs_ingestion
- **fixed** — Fix file append cleanup on failure in in_tail
- **fixed** — Reconcile files after missed inotify events in in_tail
- **fixed** — Fix handling of cfl_sds return buffers after cfl upgrade

https://fluentbit.io/announcements/v5.0.6/

##### What's Changed
* release: update to 5.0.6 by @github-actions[bot] in https://github.com/fluent/fluent-bit/pull/11785
* env: add bash-style default value operator :- by @benjaminmueggenburg-serato in https://github.com/fluent/fluent-bit/pull/11787
* lib: cfl: upgrade to v0.7.1 by @edsiper in https://github.com/fluent/fluent-bit/pull/11795
* out_kafka: partition OTLP logs by resource by @edsiper in https://github.com/fluent/fluent-bit/pull/11786
* sds: general fixes for sds_cat() usage by @edsiper in https://github.com/fluent/fluent-bit/pull/11805
* in_forward: handle unpacker allocation failure  by @edsiper in https://github.com/fluent/fluent-bit/pull/11809
* tests: prevent port binding failures in concurrent OTEL tests by @patrick-stephens in https://github.com/fluent/fluent-bit/pull/11808
* engine: ignore duplicate STOP to prevent shutdown spin by @jinyongchoi in https://github.com/fluent/fluent-bit/pull/11747
* out_azure_logs_ingestion: Plug SEGV on termination by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11800
* packaging: add support for Ubuntu 26.04 by @patrick-stephens in https://github.com/fluent/fluent-bit/pull/11802
* config: storage: Add total limit size of DLQ by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11796
* http_server: harden listener and architecture by @edsiper in https://github.com/fluent/fluent-bit/pull/11742
* tests: runtime: wait for tail truncate output by @edsiper in https://github.com/fluent/fluent-bit/pull/11810
* in_tail: fix file append cleanup on failure by @sandy2008 in https://github.com/fluent/fluent-bit/pull/11749
* in_tail: reconcile files after missed inotify events by @sandy2008 in https://github.com/fluent/fluent-bit/pull/11750
* github: workflows: Restore ok-package-test trigger behavior by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11820
* security: update policy for 5.0 and EOL 4.1 by @patrick-stephens in https://github.com/fluent/fluent-bit/pull/11818
* sds: fix handling of cfl_sds return buffers after cfl upgrade by @edsiper in https://github.com/fluent/fluent-bit/pull/11813
* tls: omit SNI for IP literal hosts by @edsiper in https://github.com/fluent/fluent-bit/pull/11827
* http_server: spawn internal server in threaded mode by @edsiper in https://github.com/fluent/fluent-bit/pull/11811

##### New Contributors
* @sandy2008 made their first contribution in https://github.com/fluent/fluent-bit/pull/11749

**Full Changelog**: https://github.com/fluent/fluent-bit/compare/v5.0.5...v5.0.6

### v5.0.5 — Fluent Bit 5.0.5

- Date: 2026-05-07
- Version: v5.0.5
- Original notes: https://github.com/fluent/fluent-bit/releases/tag/v5.0.5
- Permalink: https://whatsnew.fyi/product/fluent-bit/releases/v5.0.5

- **changed** — in_node_exporter_metrics: skip IPv6 metrics collection when disabled
- **removed** — out_logdna: remove promoted known keys
- **added** — in_ebpf: implement exec trace
- **fixed** — filter_kubernetes: destroy TLS session to prevent SSL object leak
- **changed** — aws: update support for additional regions
- **fixed** — filter_kubernetes: make memory growth rigidly on filter k8s
- **changed** — out_s3: handle otlp JSON format
- **fixed** — filter_log_to_metrics: retry timer metric append
- **fixed** — crypto: fix build with OPENSSL_NO_ENGINE
- **fixed** — opentelemetry: preserve otlp log resource grouping
- **fixed** — filter_kubernetes: destroy upstream and TLS context on happy path exit
- **fixed** — out_forward: fix retain_metadata_in_forward_mode default value
- **changed** — lib: cmetrics: upgrade to v2.1.3
- **fixed** — input: fix threaded input conditional routing for logs

https://fluentbit.io/announcements/v5.0.5/

##### What's Changed
* in_node_exporter_metrics: Skip ipv6 metrics collection when disabled by @piwai in https://github.com/fluent/fluent-bit/pull/11773
* out_logdna: remove promoted known keys by @lecaros in https://github.com/fluent/fluent-bit/pull/11755
* in_ebpf: Implement exec trace by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11714
* filter_kubernetes: destroy TLS session to prevent SSL object leak by @ShelbyZ in https://github.com/fluent/fluent-bit/pull/11730
* aws: update support for additional regions by @ShelbyZ in https://github.com/fluent/fluent-bit/pull/11733
* filter_kubernetes: make memory growth rigidly on filter k8s by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11731
* out_s3: Handle otlp JSON format by @cosmo0920 in https://github.com/fluent/fluent-bit/pull/11762
* filter_log_to_metrics: retry timer metric append by @edsiper in https://github.com/fluent/fluent-bit/pull/11774
* crypto: fix build with OPENSSL_NO_ENGINE by @yselkowitz in https://github.com/fluent/fluent-bit/pull/11771
* scripts: enable working runtime tests by @mabrarov in https://github.com/fluent/fluent-bit/pull/11724
* opentelemetry: preserve otlp log resource grouping by @edsiper in https://github.com/fluent/fluent-bit/pull/11781
* filter_kubernetes: destroy upstream and TLS context on happy path exit by @ShelbyZ in https://github.com/fluent/fluent-bit/pull/11738
* out_forward: fix retain_metadata_in_forward_mode default value (true) by @edsiper in https://github.com/fluent/fluent-bit/pull/11756
* release: update to 5.0.5 by @github-actions[bot] in https://github.com/fluent/fluent-bit/pull/11767
* lib: cmetrics: upgrade to v2.1.3 by @edsiper in https://github.com/fluent/fluent-bit/pull/11780
* input: fix threaded input conditional routing for logs by @edsiper in https://github.com/fluent/fluent-bit/pull/11783

##### New Contributors
* @yselkowitz made their first contribution in https://github.com/fluent/fluent-bit/pull/11771

**Full Changelog**: https://github.com/fluent/fluent-bit/compare/v5.0.4...v5.0.5