Description
An issue was discovered in MediaWiki before 1.31.10 and 1.32.x through 1.34.x before 1.34.4. The non-jqueryMsg version of mw.message().parse() doesn't escape HTML. This affects both message contents (which are generally safe) and the parameters (which can be based on user input). (When jqueryMsg is loaded, it correctly accepts only whitelisted tags in message contents, and escapes all parameters. Situations with an unloaded jqueryMsg are rare in practice, but can for example occur for Special:SpecialPages on a wiki with no extensions installed.)
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 | 1:1.35.0-1 | — |
| Debian 13 | mediawiki | 1:1.35.0-1 | — |
| Debian 12 | mediawiki | 1:1.35.0-1 | — |
| Debian 10 | mediawiki | 1:1.31.10-1~deb10u1 | DSA-4767-1 |
| Debian 9 | mediawiki | 1:1.27.7-1~deb9u4 | DLA-2379-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | mediawiki | No fix yet | — |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | mediawiki | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Packagist | mediawiki/core | >= 1.31.0, < 1.31.9 | 1.31.9 | GHSA-h8qx-mj6v-2934 |
| Packagist | mediawiki/core | >= 1.32.0, < 1.34.3 | 1.34.3 | GHSA-h8qx-mj6v-2934 |
| Packagist | mediawiki/core | >= 1.35.0-rc.0, < 1.35.0 | 1.35.0 | GHSA-h8qx-mj6v-2934 |
Advisories 2
- DSA-4767-1 mediawiki - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2379-1 mediawiki - security update Debian Security (DSA / DLA) · Mar 9, 2026