Description
The CheckUser extension’s Special:Investigate page has a vulnerability in the Account information tab, where specific internationalized messages are rendered without proper escaping. Attackers can exploit this by appending ?uselang=x-xss to the URL, causing reflected XSS when the UI renders affected message keys.
This issue affects Mediawiki - CheckUser extension: from 1.39.X before 1.39.13, from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Wikimedia Foundation | Mediawiki - CheckUser extension | 1.39.x – < 1.39.13, 1.42.x – < 1.42.7, 1.43.x – < 1.43.2 | 1.39.13 |
Advisories 1
- WID-SEC-2025-1525 MediaWiki Extensions und Skins: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jul 23, 2025