# Xray-core v26.3.27 — Xray-core v26.3.27

- Product: Xray-core (https://whatsnew.fyi/product/xray-core)
- Vendor: XTLS
- Date: 2026-03-27
- Version: v26.3.27
- Original notes: https://github.com/XTLS/Xray-core/releases/tag/v26.3.27
- Permalink: https://whatsnew.fyi/product/xray-core/releases/v26.3.27

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.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **added** — Add header-custom and Sudoku to Finalmask for TCP and UDP traffic customization
- **added** — Port fragment from Direct/Freedom outbound to Finalmask for TCP
- **added** — Port noise from Direct/Freedom outbound to Finalmask for UDP
- **added** — Support dialer-proxy in Finalmask and add XHTTP/3 coverage
- **added** — Add Hysteria 2 inbound and transport layer
- **added** — Add webhook support to routing rules
- **added** — Implement FullCone for both inbound and outbound WireGuard UDP
- **added** — Add complete sniffing configuration and functionality support to VLESS outbound reverse
- **added** — Add headers and User-Agent configuration to XHTTP, WS, HU, and gRPC transport layers to specify firefox, edge, or golang
- **changed** — Change XHTTP/3 congestion control to BBR by default
- **changed** — Change TTI limit range from 10-100ms to 10-5000ms for mKCP
- **changed** — Change echForceQuery default value to full, allowing only ECH-initiated connections by default
- **changed** — Move QUIC parameters congestion, brutalUp, brutalDown, and udpHop from Hysteria to Finalmask's quicParams
- **changed** — Extend dynamic Chrome User-Agent to more HTTP headers across Xray-core
- **changed** — Upgrade uTLS library with new Firefox and Safari fingerprints and add X25519MLKEM768 support
- **fixed** — Fix ACKs potentially exceeding MTU limit in mKCP to improve XDNS stability
- **fixed** — Fix possible panic in XICMP and XDNS
- **fixed** — Fix broken Browser Dialer introduced by obfuscations in previous version
- **fixed** — Fix VLESS outbound multi-peer unavailability in WireGuard
- **fixed** — Fix potential WireGuard inbound routing issues
- **fixed** — Fix server-side connection closure delay between REALITY server and target after entering bidirectional copy state
- **fixed** — Fix Online Map

##### Finalmask, mKCP, Hysteria, XHTTP, REALITY, TLS ECH, WireGuard, VLESS Reverse Proxy, Global HTTP headers' browser masquerading, API, Others

###### ~~本次重点更新内容过多~~
- **[从双重标准到“大新闻”：浅谈代理协议设计与实现上的一些本质问题与优先级区别](https://github.com/XTLS/BBS/issues/19)**
- https://github.com/XTLS/BBS/issues/21#issuecomment-4103308607
- [BlancVPN](https://blanc.link/0SIDK7Z) 正式成为赞助方之一，~~依旧面向俄罗斯人~~，这家默默赞助几个月了，还赞助了些其它开源项目

###### Finalmask https://github.com/XTLS/Xray-core/pull/5657 https://github.com/XTLS/Xray-core/pull/5685 https://github.com/XTLS/Xray-core/pull/5812 https://github.com/XTLS/Xray-core/pull/5850
- **新增 header-custom (TCP & UDP)、Sudoku (TCP & UDP)，移植了 Direct/Freedom 出站的 fragment (TCP)、noise (UDP)，最终的自定义流量外观拥有了更多可能，且均支持通过 `fm` 参数分享，基于 Xray-core 的 GUI 应尽快更新 Finalmask（类似 XHTTP extra）**
- 支持了 dialer-proxy，补上了 XHTTP/3，加上一众 TCP 协议/传输层，至此 Xray 产生的所有代理流量均能被 Finalmask
- 修复了 XICMP、XDNS 可能的 panic，**XDNS 相较于 DNSTT/Slipstream 可以通过更多 DNS，且支持代理 UDP**

###### mKCP https://github.com/XTLS/Xray-core/pull/5773 https://github.com/XTLS/Xray-core/pull/5755
- **修复了 ACKs 可能超出 MTU 限制的问题，使 XDNS 更加稳定**
- 将 TTI 限制由 10\~100 毫秒改为了 10\~5000 毫秒
- https://github.com/XTLS/Xray-core/discussions/716 分享链接标准新增 `mtu`、`tti` 两项，~~还是为了 XDNS~~

###### Hysteria https://github.com/XTLS/Xray-core/pull/5679 https://github.com/XTLS/Xray-core/pull/5782 https://github.com/XTLS/Xray-core/pull/5772
- **新增 Hysteria 2 入站与传输层，~~至此 Xray 支持了完整的 Hysteria 2，甚至 Finalmask 不只有 Salamander~~**
- 注意若要使用端口跳跃，入站应当只监听一个端口，并使用 iptables 转发其它端口的流量
- 将 `congestion`、`brutalUp`、`brutalDown`、`udpHop` 等 QUIC 参数移到了 Finalmask 的 `quicParams`

###### XHTTP https://github.com/XTLS/Xray-core/pull/5711 https://github.com/XTLS/Xray-core/pull/5720 https://github.com/XTLS/Xray-core/pull/5803
- **XHTTP/3 拥塞控制改为默认 BBR ，同样支持通过 Finalmask 的 `quicParams` 设置 "force-brutal"、`udpHop` 等**
- 修复了上个版本新增 obfuscations 所引入的一些问题，比如 broken Browser Dialer，顺带一些增强
- 优化了一些代码与内存占用，~~快去测测 iOS~~

###### REALITY https://github.com/XTLS/Xray-core/commit/157e65b34d32363528088c592d4e415d84f01a63 https://github.com/XTLS/Xray-core/commit/2320416ca3869d7818b9d86b749259a75fd3e103 https://github.com/XTLS/Xray-core/pull/5738 https://github.com/XTLS/Xray-core/pull/5759
- **基于前段时间的经验，非 443 端口、“偷苹果”极易导致服务器 IP 被封锁，故对这两个行为输出警告信息**
- 服务端启动时自动对 target 的 maxUselessRecords 进行四档探测并应用于自身，默认值 32
- 其它一些修复，比如修复了服务端进入双向拷贝状态后，服务端与 target 间可能未及时关闭连接的问题

###### TLS ECH https://github.com/XTLS/Xray-core/pull/5725
- 避免了 WSS & HUS 的 outer ALPN 仍为 http/1.1，~~虽然这一行为与浏览器不同但 ALPN http/1.1 会被重点关照所以~~
- **修改了 `echForceQuery` 的默认值为 "full"，即默认只允许以 ECH 发起连接**
- 顺便升级了 uTLS 库更新了新版 Firefox、Safari 指纹，支持 X25519MLKEM768，like Chrome

###### WireGuard https://github.com/XTLS/Xray-core/pull/5833 https://github.com/XTLS/Xray-core/pull/5554 https://github.com/XTLS/Xray-core/pull/5843
- **出入站 UDP 均实现了 FullCone，提醒一下结合 Finalmask 后它拥有比其它 WireGuard 变种更强大的伪装能力**
- 修复了出站 multi-peer 不可用的问题
- 修复了入站可能的路由问题

###### VLESS Reverse Proxy https://github.com/XTLS/Xray-core/pull/5837 https://github.com/XTLS/Xray-core/pull/5752
- **VLESS 出站的 `reverse`（实际上是一个入站）添加了完整的 `sniffing` 配置项与功能支持**
- VLESS 入站建立新的反向 mux 连接（可能同时新建出站）后立即检查 burstObservatory

###### Global HTTP headers' browser masquerading https://github.com/XTLS/Xray-core/pull/5802 https://github.com/XTLS/Xray-core/pull/5689
- 上个版本改的“Xray-core HTTP 请求的 User-Agent 均由 Go 改为动态 Chrome”扩展到了更多 headers
- **XHTTP、WS、HU、gRPC 传输层可设置 `headers` `User-Agent` 来指定 "firefox"/"edge"/"golang"**

###### API https://github.com/XTLS/Xray-core/pull/5722 https://github.com/XTLS/Xray-core/pull/5732
- **为 `routing` 的 `rules` 添加了 `webhook` 支持**
- 修复了 Online Map

###### Others https://github.com/XTLS/Xray-core/pull/5680 https://github.com/XTLS/Xray-core/pull/4584
- 该版本升级了一些依赖，并使用 Go 1.26.1 拉满 inline 编译，已 tag v1.260327.0
- **其它一些改进与修复，感谢所有贡献者，详见下方完整 change log**

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