CVE-2021-42391 json
Divide-by-zero in Clickhouse's Gorilla compression codec when parsing a malicious query.
published 4y ago modified 4mo ago also EUVD-2021-29362
- cvss
- 6.5
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.4%
- EPSS 1.4% chance of exploitation in 30 days, percentile 72%
- public exploits
- 0
- none known
Summary
Divide-by-zero in Clickhouse's Gorilla compression codec when parsing a malicious query. The first byte of the compressed buffer is used in a modulo operation without being checked for 0.
Patch / fix
- yandex clickhouse 21.10.2.15-stable
Is CVE-2021-42391 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerExploit prediction
1.37% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-09).
Exploits and checks
- jfrog.com https://jfrog.com/blog/7-rce-and-dos-vulnerabilities-found-in-clickhouse-dbms referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
| NVD | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:N/I:N/A:P |
Affected products
- yandex clickhouse
Classification
- Weakness
-
- CWE-369 Divide By Zero
References
-
jfrog.com
/blog/7-rce-and-dos-vulnerabilities-found-in-clickhouse-dbms
exploit, third-party-advisory
Sources
- CVE List CVE-2021-42391
- NVD CVE-2021-42391
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.