In MediaWiki before 1.34.1, users can add various Cascading Style Sheets (CSS) classes (which can affect what content is shown or hidden in the user interface) to arbitrary DOM nodes via HTML content within a MediaWiki page. This occurs because jquery.makeCollapsible allows applying an event handler to any Cascading Style Sheets (CSS) selector. There is no known way to exploit this for cross-site scripting (XSS).

An issue was discovered in the AbuseFilter extension for MediaWiki. includes/special/SpecialAbuseLog.php allows attackers to obtain sensitive information, such as deleted/suppressed usernames and summaries, from AbuseLog revision data. This affects REL1_32 and REL1_33.

An issue was discovered in the CheckUser extension through 1.35.0 for MediaWiki. Oversighted edit summaries are still visible in CheckUser results in violation of MediaWiki's permissions model.

In the MobileFrontend extension for MediaWiki, XSS exists within the edit summary field of the watchlist feed. This affects REL1_31, REL1_32, and REL1_33.

In the GlobalBlocking extension before 2020-03-10 for MediaWiki through 1.34.0, an issue related to IP range evaluation resulted in blocked users re-gaining escalated privileges. This is related to the case in which an IP address is contained in two ranges, one of which is locally disabled.

An issue was discovered in the Widgets extension through 1.4.0 for MediaWiki. Improper title sanitization allowed for the execution of any wiki page as a widget (as defined by this extension) via MediaWiki's {{#widget:}} parser function.

MediaWiki before 1.18.5, and 1.19.x before 1.19.2 saves passwords in the local database, (1) which could make it easier for context-dependent attackers to obtain cleartext passwords via a brute-force attack or, (2) when an authentication plugin returns a false in the strict function, could allow remote attackers to use old passwords for non-existing accounts in an external authentication system via unspecified vectors.

The CentralNotice extension for MediaWiki before 1.19.9, 1.20.x before 1.20.8, and 1.21.x before 1.21.3 sets the Cache-Control header to cache session cookies when a user is autocreated, which allows remote attackers to authenticate as the created user.

The CentralAuth extension for MediaWiki before 1.19.10, 1.2x before 1.21.4, and 1.22.x before 1.22.1 allows remote attackers to obtain usernames via vectors related to writing the names to the DOM of a page.

Cross-site scripting (XSS) vulnerability in MediaWiki 1.19.9 before 1.19.10, 1.2x before 1.21.4, and 1.22.x before 1.22.1 allows remote attackers to inject arbitrary web script or HTML via unspecified CSS values.

The Scribunto extension for MediaWiki allows remote attackers to obtain the rollback token and possibly other sensitive information via a crafted module, related to unstripping special page HTML.

The WikibaseMediaInfo extension 1.35 for MediaWiki allows XSS because of improper template syntax within the PropertySuggestionsWidget template (in the templates/search/PropertySuggestionsWidget.mustache+dom file).

The MinervaNeue Skin in MediaWiki from 2019-11-05 to 2019-12-13 (1.35 and/or 1.34) mishandles certain HTML attributes, as demonstrated by IMG onmouseover= (impact is XSS) and IMG src=http (impact is disclosing the client's IP address). This can occur within a talk page topical header that is viewed within a mobile (MobileFrontend) context.

includes/libs/IEUrlExtension.php in the MediaWiki API in MediaWiki 1.19.x before 1.19.8, 1.20.x before 1.20.7, and 1.21.x before 1.21.2 does not properly detect extensions when there are an even number of "." (period) characters in a string, which allows remote attackers to conduct cross-site scripting (XSS) attacks via the siprop parameter in a query action to wiki/api.php.

MediaWiki through 1.33.1 allows attackers to bypass the Title_blacklist protection mechanism by starting with an arbitrary title, establishing a non-resolvable redirect for the associated page, and using redirect=1 in the action API when editing that page.

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.