Description
Incomplete blacklist vulnerability in Sanitizer::checkCss in MediaWiki before 1.19.9, 1.20.x before 1.20.8, and 1.21.x before 1.21.3 allows remote attackers to conduct cross-site scripting (XSS) attacks via certain non-ASCII characters in CSS, as demonstrated using variations of "expression" containing (1) full width characters or (2) IPA extensions, which are converted and rendered by Internet Explorer.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | mediawiki | 1:1.19.8+dfsg-2.2 | — |
| Debian 13 | mediawiki | 1:1.19.8+dfsg-2.2 | — |
| Debian 12 | mediawiki | 1:1.19.8+dfsg-2.2 | — |
| Debian 7 | mediawiki | 1:1.19.14+dfsg-0+deb7u1 | DSA-2891-1 |
| Debian 7 | mediawiki-extensions | 3.5~deb7u1 | DSA-2891-1 |
Advisories 1
- DSA-2891-1 mediawiki - security update Debian Security (DSA / DLA) · Mar 9, 2026
References
- 57472 third-party-advisory
- DSA-2891 vendor-advisory
- https://bugzilla.wikimedia.org/attachment.cgi?id=13452&action=diff
- [MediaWiki-announce] 20131114 MediaWiki Security Release: 1.21.3, 1.20.8 and 1.19.9 mailing-list
- FEDORA-2013-21856 vendor-advisory
- 63761 vdb-entry
- FEDORA-2013-21874 vendor-advisory
- https://bugzilla.wikimedia.org/show_bug.cgi?id=55332