Description
An issue was discovered in MediaWiki before 1.35.1. Missing users (accounts that don't exist) and hidden users (accounts that have been explicitly hidden due to being abusive, or similar) that the viewer cannot see are handled differently, exposing sensitive information about the hidden status to unprivileged viewers. This exists on various code paths.
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