An issue was discovered in SecurePoll in the Growth extension in MediaWiki through 1.36.2. Simple polls allow users to create alerts by changing their User-Agent HTTP header and submitting a vote.
An issue was discovered in the GlobalWatchlist extension in MediaWiki through 1.36.2. The rev-deleted-user and ntimes messages were not properly escaped and allowed for users to inject HTML and JavaScript.
An issue was discovered in the Growth extension in MediaWiki through 1.36.2. On any Wiki with the Mentor Dashboard feature enabled, users can login with a mentor account and trigger an XSS payload (such as alert) via Growthexperiments-mentor-dashboard-mentee-overview-no-js-fallback.
An issue was discovered in the Growth extension in MediaWiki through 1.36.2. Any admin can add arbitrary JavaScript code to the Newcomer home page footer, which can be executed by viewers with zero edits.
An issue was discovered in the Translate extension in MediaWiki through 1.36.2. Oversighters cannot undo revisions or oversight on pages where they suppressed information (such as PII). This allows oversighters to whitewash revisions.
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.
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.
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 Private Domains extension for MediaWiki through 1.37.2 (before 1ad65d4c1c199b375ea80988d99ab51ae068f766) allows CSRF for editing pages that store the extension's configuration. The attacker must trigger a POST request to Special:PrivateDomains.