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Vulnerability record · CVE-2021-43305 · published 14 March 2022

CVE-2021-43305: Clickhouse heap-based buffer overflow vulnerability

Clickhouse · Clickhouse

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. This issue is very similar to CVE-2021-43304, but the vulnerable copy operation is in a different wildCopy call.

8.8 CVSS 3.1 High EPSS 1.7% · top 22.9% CWE-122 · Heap-based buffer overflowCWE-787 · Out-of-bounds write
8.8CVSS 3.1 base score, v2 6.5
1.7%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
4References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

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. This issue is very similar to CVE-2021-43304, but the vulnerable copy operation is in a different wildCopy call.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://jfrog.com/blog/7-rce-and-dos-vulnerabilities-found-in-clickhouse-dbms ExploitThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/11/msg00002.html Mailing ListThird Party Advisory
https://jfrog.com/blog/7-rce-and-dos-vulnerabilities-found-in-clickhouse-dbms ExploitThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/11/msg00002.html Mailing ListThird Party Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-43305), CISA KEV, FIRST EPSS (scores of 2026-11-11). This page is refreshed as NVD updates the record.