The VisualEditor extension through 1.34 for MediaWiki allows XSS via pasted content containing an element with a data-ve-clipboard-key attribute.

MediaWiki before 1.19.4 and 1.20.x before 1.20.3 contains an error in the api.php script which allows remote attackers to obtain sensitive information.

MediaWiki before 1.19.4 and 1.20.x before 1.20.3 allows remote attackers to cause a denial of service (application crash) by sending a specially crafted request.

An issue was discovered in the AbuseFilter extension through 1.34 for MediaWiki. Once a specific abuse filter has (accidentally or otherwise) been made public, its previous versions can be exposed, thus potentially disclosing private or sensitive information within the filter's definition.

A cross-site scripting (XSS) vulnerability in MediaWiki before 1.19.5 and 1.20.x before 1.20.4 and allows remote attackers to inject arbitrary web script or HTML via Lua function names.

An issue was discovered in the AbuseFilter extension through 1.34 for MediaWiki. Previously hidden (restricted) AbuseFilter filters were viewable (or their differences were viewable) to unprivileged users, thus disclosing potentially sensitive information.

mediawiki allows deleted text to be exposed

An issue was discovered in the CheckUser extension through 1.34 for MediaWiki. Certain sensitive information within oversighted edit summaries made available via the MediaWiki API was potentially visible to users with various levels of access to this extension. Said users should not have been able to view these oversighted edit summaries via the MediaWiki API.

In MediaWiki through 1.33.0, Special:Redirect allows information disclosure of suppressed usernames via a User ID Lookup.

In the MobileFrontend extension 1.31 through 1.33 for MediaWiki, XSS exists within the edit summary field in includes/specials/MobileSpecialPageFeed.php.