An issue was discovered in MediaWiki through 1.37.1. The CentralAuth extension mishandles a ttl issue for groups expiring in the future.

An XSS issue was discovered in MediaWiki before 1.35.6, 1.36.x before 1.36.4, and 1.37.x before 1.37.2. The widthheight, widthheightpage, and nbytes properties of messages are not escaped when used in galleries or Special:RevisionDelete.

MediaWiki before 1.23.16, 1.24.x through 1.27.x before 1.27.2, and 1.28.x before 1.28.1 allows remote attackers to discover the IP addresses of Wiki visitors via a style="background-image: attr(title url);" attack within a DIV element that has an attacker-controlled URL in the title attribute.

ShortDescription is a MediaWiki extension that provides local short description support. A cross-site scripting (XSS) vulnerability exists in versions prior to 2.3.4. On a wiki that has the ShortDescription enabled, XSS can be triggered on any page or the page with the action=info parameter, which displays the shortdesc property. This is achieved using the wikitext `{{SHORTDESC:<img src=x onerror=alert()>}}`. This issue has a patch in version 2.3.4.

In MediaWiki through 1.37, the Special:ImportFile URI (aka FileImporter) allows XSS, as demonstrated by the clientUrl parameter.

In MediaWiki through 1.37, Wikibase item descriptions allow XSS, which is triggered upon a visit to an action=info URL (aka a page-information sidebar).

In MediaWiki through 1.37, XSS can occur in Wikibase because an external identifier property can have a URL format that includes a $1 formatter substitution marker, and the javascript: URL scheme (among others) can be used.

In MediaWiki through 1.37, blocked IP addresses are allowed to edit EntitySchema items.

An issue was discovered in MediaWiki before 1.35.5, 1.36.x before 1.36.3, and 1.37.x before 1.37.1. It is possible to use action=edit&undo= followed by action=mcrundo and action=mcrrestore to view private pages on a private wiki that has at least one page set in $wgWhitelistRead.

An issue was discovered in MediaWiki before 1.35.5, 1.36.x before 1.36.3, and 1.37.x before 1.37.1. By using an action=rollback query, attackers can view private wiki contents.