# ClickHouse v26.6.4.55-stable — Release v26.6.4.55-stable

- Product: ClickHouse (https://whatsnew.fyi/product/clickhouse)
- Vendor: ClickHouse
- Date: 2026-09-01
- Version: v26.6.4.55-stable
- Original notes: https://github.com/ClickHouse/ClickHouse/releases/tag/v26.6.4.55-stable
- Permalink: https://whatsnew.fyi/product/clickhouse/releases/v26.6.4.55-stable
- Labels: Machine-generated from commit messages — the vendor published no release notes

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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- **fixed** — Use-after-free on a sparse join key in a direct dictionary join
- **fixed** — Serialization of Map-valued settings in access entities
- **fixed** — Distributed index analysis with projections producing wrong results
- **fixed** — Out-of-bounds write in text index front-coding deserialization
- **fixed** — CREATE OR REPLACE MATERIALIZED VIEW ... POPULATE losing the source subscription
- **fixed** — Trivial count optimization incorrectly applied when the aggregate argument contains arrayJoin
- **fixed** — Out-of-bounds read in formatRowNoNewline with empty rows
- **fixed** — Out-of-bounds memory exposure in query results
- **fixed** — Various parsing and schema reader recursion depth limits and PostgreSQL startup message size bounds
- **fixed** — Multiple query execution and data handling issues including KeeperMap metadata compatibility, row policies bypassing, LowCardinality search, aggregate function deserialization, Variant discriminator validation, ZooKeeper multi requests, and distributed query planning