Description
The CheckUser extension’s Special:CheckUser interface is vulnerable to reflected XSS via the rev-deleted-user message. This message is rendered without proper escaping, making it possible to inject JavaScript through the uselang=x-xss language override mechanism.
This issue affects Mediawiki - CheckUser extension: 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 | 1.42.x – < 1.42.7, 1.43.x – < 1.43.2 | 1.42.7 |
Advisories 1
- WID-SEC-2025-1525 MediaWiki Extensions und Skins: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jul 23, 2025