Description
MediaWiki before 1.35.1 allows XSS via BlockLogFormatter.php. Language::translateBlockExpiry itself does not escape in all code paths. For example, the return of Language::userTimeAndDate is is always unsafe for HTML in a month value. This affects MediaWiki 1.12.0 and later.
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 | 1:1.35.1-1 | — |
| Debian 13 | mediawiki | 1:1.35.1-1 | — |
| Debian 12 | mediawiki | 1:1.35.1-1 | — |
| Debian 10 | mediawiki | 1:1.31.12-1~deb10u1 | DSA-4816-1 |
| Debian 9 | mediawiki | 1:1.27.7-1~deb9u7 | DLA-2504-1 |
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-4816-1 mediawiki - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2504-1 mediawiki - security update Debian Security (DSA / DLA) · Mar 9, 2026