Description
Heap out-of-bounds read in Clickhouse's LZ4 compression codec when parsing a malicious query. As part of the LZ4::decompressImpl() loop, a 16-bit unsigned user-supplied value ('offset') is read from the compressed data. The offset is later used in the length of a copy operation, without checking the upper bounds of the source of the copy operation.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| yandex | clickhouse | unspecified – < 21.10.2.15-stable | 21.10.2.15-stable |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 12 | clickhouse | 18.16.1+ds-7.3 | — |
| Debian 10 | clickhouse | 18.16.1+ds-4+deb10u1 | DLA-3176-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | clickhouse | 18.16.1+ds-7ubuntu0.1 | USN-6933-1 |
Advisories 2
- DLA-3176-1 clickhouse - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-6933-1 clickhouse vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026