CVE-2021-36126

CRITICAL

MediaWiki < 1.36 - Denial of Service via AbuseFilter Block Message Fallback

Title source: llm
STIX 2.1

Description

An issue was discovered in the AbuseFilter extension in MediaWiki through 1.36. If the MediaWiki:Abusefilter-blocker message is invalid within the content language, the filter user falls back to the English version, but that English version could also be invalid on a wiki. This would result in a fatal error, and potentially fail to block or restrict a potentially nefarious user.

References (2)

Core 2
Core References
Exploit, Issue Tracking, Patch, Vendor Advisory x_refsource_misc
https://phabricator.wikimedia.org/T284364

Scores

CVSS v3 9.8
EPSS 0.0034
EPSS Percentile 56.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Details

Status published
Products (1)
mediawiki/mediawiki < 1.36
Published Jul 02, 2021
Tracked Since Feb 18, 2026