CVE-2021-43304: clickhouse Heap-based Buffer Overflow
Vulnerability summary
CVE-2021-43304 is a high (CVSS 8.8) Heap-based Buffer Overflow vulnerability in clickhouse. EPSS estimates a 1.67% chance of exploitation in the next 30 days, higher than 76.6% of scored vulnerabilities. 1 public exploit is recorded.
Advisory lineage
Upstream 0 · Downstream 1Timeline
- 14-03-2022PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 2 sources · 2 versions- OSV · DebianEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
1.67%
Chance of exploitation in the next 30 days
Percentile
77%
Versus all other CVEs
30-day change
No change 0.00 pp
From 1.67% on 22-09-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 foundExploit Reference (jfrog.com)
Maturity: unknown
Weaknesses
CWE · root cause- CWE-122Heap-based Buffer OverflowA heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
- CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.
Affected systems
Debian2 products
- clickhouse< 18.16.1+ds-7.3
- debian_linuxEOL10.0
Clickhouse1 product
- clickhouse< 21.10.2.15
Yandex1 product
- clickhouse≥ unspecified, < 21.10.2.15-stable
3 vendors · 4 products
