An issue was discovered in the Metrolook skin for MediaWiki through 1.42.1. There is stored XSS via MediaWiki:Sidebar top-level menu entries.

An issue was discovered in the GlobalBlocking extension in MediaWiki before 1.40.2. For a Special:GlobalBlock?uselang=x-xss URI, i18n-based XSS can occur via the parentheses message. This affects subtitle links in buildSubtitleLinks.

An issue was discovered in the SportsTeams extension for MediaWiki before 1.35.12, 1.36.x through 1.39.x before 1.39.5, and 1.40.x before 1.40.1. It does not check for the anti-CSRF edit token in Special:SportsTeamsManager and Special:UpdateFavoriteTeams.

An issue was discovered in the ProofreadPage extension for MediaWiki before 1.35.12, 1.36.x through 1.39.x before 1.39.5, and 1.40.x before 1.40.1. XSS can occur via formatNumNoSeparators.

An issue was discovered in the Wikibase extension for MediaWiki before 1.35.12, 1.36.x through 1.39.x before 1.39.5, and 1.40.x before 1.40.1. During item merging, ItemMergeInteractor does not have an edit filter running (e.g., AbuseFilter).

An issue was discovered in the Wikibase extension for MediaWiki before 1.35.12, 1.36.x through 1.39.x before 1.39.5, and 1.40.x before 1.40.1. There is no rate limit for merging items.

An issue was discovered in the SportsTeams extension for MediaWiki before 1.35.12, 1.36.x through 1.39.x before 1.39.5, and 1.40.x before 1.40.1. SportsTeams: Special:SportsManagerLogo and Special:SportsTeamsManagerLogo do not check for the sportsteamsmanager user right, and thus an attacker may be able to affect pages that are concerned with sports teams.

An issue was discovered in the PageTriage extension for MediaWiki before 1.35.12, 1.36.x through 1.39.x before 1.39.5, and 1.40.x before 1.40.1. Usernames of hidden users are exposed.

An issue was discovered in the CheckUser extension for MediaWiki before 1.35.12, 1.36.x through 1.39.x before 1.39.5, and 1.40.x before 1.40.1. A user can use a rest.php/checkuser/v0/useragent-clienthints/revision/ URL to store an arbitrary number of rows in cu_useragent_clienthints, leading to a denial of service.

An issue was discovered in includes/page/Article.php in MediaWiki 1.36.x through 1.39.x before 1.39.5 and 1.40.x before 1.40.1. Deleted revision existence is leaked due to incorrect permissions being checked. This reveals that a given revision ID belonged to the given page title, and its timestamp, both of which are not supposed to be public information.

An issue was discovered in ApiPageSet.php in MediaWiki before 1.35.12, 1.36.x through 1.39.x before 1.39.5, and 1.40.x before 1.40.1. It allows attackers to cause a denial of service (unbounded loop and RequestTimeoutException) when querying pages redirected to other variants with redirects and converttitles set.

MediaWiki: Manualthumb bypasses badFile lookup

An issue was discovered in MediaWiki before 1.35.11, 1.36.x through 1.38.x before 1.38.7, 1.39.x before 1.39.4, and 1.40.x before 1.40.1. It is possible to bypass the Bad image list (aka badFile) by using the thumb parameter (aka Manualthumb) of the File syntax.

mediawiki: global DoS via site admin

An issue was discovered in the MediaWiki through 1.38.2. The community configuration pages for the GrowthExperiments extension could cause a site to become unavailable due to insufficient validation when certain actions (including page moves) were performed.

mediawiki: Username not escaped in the contributions-title message

An issue was discovered in MediaWiki before 1.37.3 and 1.38.x before 1.38.1. The contributions-title, used on Special:Contributions, is used as page title without escaping. Hence, in a non-default configuration where a username contains HTML entities, it won't be escaped.

mediawiki: Cross-site Scripting

An issue was discovered in MediaWiki before 1.35.7, 1.36.x and 1.37.x before 1.37.3, and 1.38.x before 1.38.1. XSS can occur in configurations that allow a JavaScript payload in a username. After account creation, when it sets the page title to "Welcome" followed by the username, the username is not escaped: SpecialCreateAccount::successfulAction() calls ::showSuccessPage() with a message as second parameter, and OutputPage::setPageTitle() uses text().

An issue was discovered in MediaWiki through 1.38.1. The lemma length of a Wikibase lexeme is currently capped at a thousand characters. Unfortunately, this length is not validated, allowing much larger lexemes to be created, which introduces various denial-of-service attack vectors within the Wikibase and WikibaseLexeme extensions. This is related to Special:NewLexeme and Special:NewProperty.

The Nimbus skin for MediaWiki through 1.37.2 (before 6f9c8fb868345701d9544a54d9752515aace39df) allows XSS in Advertise link messages.

The admin API module in the QuizGame extension for MediaWiki through 1.37.2 (before 665e33a68f6fa1167df99c0aa18ed0157cdf9f66) omits a check for the quizadmin user.

The FanBoxes extension for MediaWiki through 1.37.2 (before 027ffb0b9d6fe0d823810cf03f5b562a212162d4) allows Special:UserBoxes CSRF.

The SemanticDrilldown extension for MediaWiki through 1.37.2 (before e688bdba6434591b5dff689a45e4d53459954773) allows SQL injection with certain '-' and '_' constraints.