CVE-2021-43304: Clickhouse

High severity, CVSS 8.8. EPSS: 1.7% chance of exploitation in the next 30 days.

Heap buffer overflow in Clickhouse's LZ4 compression codec when parsing a malicious query. There is no verification that the copy operations in the LZ4::decompressImpl loop and especially the arbitrary copy operation wildCopy<copy_amount>(op, ip, copy_end), don’t exceed the destination buffer’s limits.

Affected products

• Clickhouse Clickhouse: before 21.10.2.15 (fixed in 21.10.2.15)
• Debian Debian Linux: version 10.0 only

Published 2022-03-14. Last modified 2026-06-17.