CVE-2021-36126
CVSS v3
9.8
CRITICAL
EPSS Score
1.2 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
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.
Technical details
- Published
- 2021-07-02
Frequently asked questions
What is CVE-2021-36126?
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.
Is CVE-2021-36126 actively exploited?
Active exploitation of CVE-2021-36126 has not been confirmed. Its EPSS score was 1.2% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-36126?
CVE-2021-36126 has a CVSS v3 base score of 9.8 (CRITICAL severity).
Is CVE-2021-36126 affecting your environment?
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