An issue was discovered in the CheckUser extension in MediaWiki before 1.35.14, 1.36.x through 1.39.x before 1.39.6, and 1.40.x before 1.40.2. XSS can occur via message definitions. e.g., in SpecialCheckUserLog.
| Software | From | Fixed in |
|---|---|---|
| mediawiki / mediawiki | - | 1.35.14 |
| mediawiki / mediawiki | 1.36.0 | 1.39.6 |
| mediawiki / mediawiki | 1.40.0 | 1.40.2 |