High (8.1). EPSS 1.6% chance of exploitation in the next 30 days.
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 lower bounds of the source of the copy operation.
Severity
CVSS 3.1
8.1 high
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
EPSS
1.6% chance of exploitation in the next 30 days; higher than 75% of CVEs (scores of 2026-10-31)