Skip to content
Fencer Vulns
medium 6.5

CVE-2021-42389 json

Divide-by-zero in Clickhouse's Delta compression codec when parsing a malicious query.

published 2022-03-14 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-29360

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 69%
public exploits
0
none known

Summary

Divide-by-zero in Clickhouse's Delta 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

Exploit prediction

1.26% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-08).

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 4.0 AV:N/AC:L/Au:S/C:N/I:N/A:P

Affected products

  • yandex clickhouse

Classification

Weakness

References

Sources

Fencer Vulns 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.