An issue was discovered in the Cargo extension for MediaWiki through 1.39.3. It allows one to store javascript: URLs in URL fields, and automatically links these URLs.

An issue was discovered in the CheckUser extension for MediaWiki through 1.39.3. In Special:CheckUser, a check of the "get edits" type is vulnerable to HTML injection through the User-Agent HTTP request header.

An issue was discovered in the Cargo extension for MediaWiki through 1.39.3. XSS can occur in Special:CargoQuery via a crafted page item when using the default format.

An issue was discovered in the GoogleAnalyticsMetrics extension for MediaWiki through 1.39.3. The googleanalyticstrackurl parser function does not properly escape JavaScript in the onclick handler and does not prevent use of javascript: URLs.

An issue was discovered in MediaWiki before 1.35.11, 1.36.x through 1.38.x before 1.38.7, and 1.39.x before 1.39.4. BlockLogFormatter.php in BlockLogFormatter allows XSS in the partial blocks feature.

An issue was discovered in MediaWiki before 1.35.8, 1.36.x and 1.37.x before 1.37.5, and 1.38.x before 1.38.3. Upon an action=rollback operation, the alreadyrolled message can leak a user name (when the user has been revision deleted/suppressed).

An issue was discovered in the VisualEditor extension in MediaWiki before 1.31.13, and 1.32.x through 1.35.x before 1.35.2. . When using VisualEditor to edit a MediaWiki user page belonging to an existing, but hidden, user, VisualEditor will disclose that the user exists. (It shouldn't because they are hidden.) This is related to ApiVisualEditor.

An issue was discovered in MediaWiki before 1.35.10, 1.36.x through 1.38.x before 1.38.6, and 1.39.x before 1.39.3. An auto-block can occur for an untrusted X-Forwarded-For header.

An issue was discovered in the GrowthExperiments extension for MediaWiki through 1.39.3. Attackers might be able to see edits for which the username has been hidden, because there is no check for rev_deleted.

An issue was discovered in the CheckUser extension for MediaWiki through 1.39.3. When a user with checkuserlog permissions makes many CheckUserLog API requests in some configurations, denial of service can occur (RequestTimeoutException or upstream request timeout).