Description
An issue was discovered in MediaWiki before 1.35.11, 1.36.x through 1.38.x before 1.38.7, and 1.39.x before 1.39.4. BlockLogFormatter.php in BlockLogFormatter allows XSS in the partial blocks feature.
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 | 1:1.39.4-1 | — |
| Debian 13 | mediawiki | 1:1.39.4-1 | — |
| Debian 12 | mediawiki | 1:1.39.4-1~deb12u1 | DSA-5447-1 |
| Debian 11 | mediawiki | 1:1.35.11-1~deb11u1 | DSA-5447-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | mediawiki | No fix yet | — |
| Ubuntu 26.04 LTS | mediawiki | No fix yet | — |
| Ubuntu 25.10 | mediawiki | No fix yet | — |
| Ubuntu 18.04 LTS | mediawiki | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 24.04 LTS | mediawiki | No fix yet | — |
| Ubuntu Pro 22.04 LTS | mediawiki | No fix yet | — |
| Ubuntu Pro 20.04 LTS | mediawiki | No fix yet | — |
Advisories 2
- DSA-5447-1 mediawiki - security update Debian Security (DSA / DLA) · Mar 9, 2026
- WID-SEC-2023-1570 MediaWiki: Schwachstelle ermöglicht Cross-Site Scripting BSI CERT-Bund (WID) · Aug 24, 2023
References
- https://phabricator.wikimedia.org/T332889
- https://www.mediawiki.org/wiki/Release_notes/1.40#Other_changes_in_1.40
- DSA-5447 vendor-advisory
- FEDORA-2023-1fcaba0998 vendor-advisory
- FEDORA-2023-d8ae3c122e vendor-advisory
- FEDORA-2023-7e9d6015f6 vendor-advisory