An issue was discovered in MediaWiki through 1.36.2.

published 2021-10-06 5y ago modified 2026-06-17 4mo ago also BIT-mediawiki-2021-42040 , EUVD-2021-29028

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.2%; EPSS 1.2% chance of exploitation in 30 days, percentile 67%
public exploits: 0; none known

An issue was discovered in MediaWiki through 1.36.2. A parser function related to loop control allowed for an infinite loop (and php-fpm hang) within the Loops extension because egLoopsCountLimit is mishandled. This could lead to memory exhaustion.

Patch / fix

fixed in 1 links 2

bitnami mediawiki 1.36.3

phabricator.wikimedia.org/T287347 advisory
gerrit.wikimedia.org/r/q/I0caf6f129f94612b5bcf406a171aa5ffedea1f80 advisory

Is CVE-2021-42040 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

1.16% chance of exploitation in the next 30 days, higher than 67% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/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
OSV	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem	package	affected	fixed in
bitnami	mediawiki	<1.36.3	1.36.3

Classification

Weakness

CWE-835 Loop with Unreachable Exit Condition

References

phabricator.wikimedia.org /T287347
patch, vendor-advisory, web
gerrit.wikimedia.org /r/q/I0caf6f129f94612b5bcf406a171aa5ffedea1f80
patch, vendor-advisory, web
nvd.nist.gov /vuln/detail/CVE-2021-42040
web

Sources

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.