CVE-2020-35478

MEDIUM 6.1CVE-2020-35478 · Published 18/12/2020 · updated 17/06/2026

In short

CVE-2020-35478 is a MEDIUM (CVSS 6.1) vulnerability affecting mediawiki (mediawiki).
Chance of exploitation in the next 30 days (EPSS): 1.4%, higher than 71.9% of all vulnerabilities.
Fix: update to 1.35.1 or later.

Package	Affected versions	Patched versions
mediawiki mediawiki	`≥ 1.33.0, < 1.35.1`	`1.35.1`

Description

MediaWiki before 1.35.1 allows XSS via BlockLogFormatter.php. MediaWiki:blanknamespace potentially can be output as raw HTML with SCRIPT tags via LogFormatter::makePageLink(). This affects MediaWiki 1.33.0 and later.

References

lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/STT5Z4A3BCXVH3WIPICWU2FP4IPIMUPC
lists.wikimedia.org/pipermail/mediawiki-announce/2020-December/000268.html · Mailing List
phabricator.wikimedia.org/T268938 · Exploit

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Package

Affected versions

Patched versions

mediawiki

≥ 1.33.0, < 1.35.1

1.35.1

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