An issue was discovered in the GrowthExperiments extension for MediaWiki through 1.39.3. Attackers might be able to see edits for which the username has been hidden, because there is no check for rev_deleted.

An issue was discovered in the CheckUser extension for MediaWiki through 1.39.3. When a user with checkuserlog permissions makes many CheckUserLog API requests in some configurations, denial of service can occur (RequestTimeoutException or upstream request timeout).

An issue was discovered in the GrowthExperiments extension for MediaWiki through 1.39.3. The UserImpactHandler for GrowthExperiments inadvertently returns the timezone preference for arbitrary users, which can be used to de-anonymize users.

A vulnerability classified as problematic has been found in DaSchTour matomo-mediawiki-extension up to 2.4.2 on MediaWiki. This affects an unknown part of the file Piwik.hooks.php of the component Username Handler. The manipulation leads to cross site scripting. It is possible to initiate the attack remotely. The complexity of an attack is rather high. The exploitability is told to be difficult. The exploit has been disclosed to the public and may be used. Upgrading to version 2.4.3 is able to address this issue. The patch is named 681324e4f518a8af4bd1f93867074c728eb9923d. It is recommended to upgrade the affected component. The associated identifier of this vulnerability is VDB-220203.

An issue was discovered in the CheckUser extension for MediaWiki through 1.39.x. Various components of this extension can expose information on the performer of edits and logged actions. This information should not allow public viewing: it is supposed to be viewable only by users with suppression rights.

An issue was discovered in MediaWiki before 1.35.9, 1.36.x through 1.38.x before 1.38.5, and 1.39.x before 1.39.1. CheckUser TokenManager insecurely uses AES-CTR encryption with a repeated (aka re-used) nonce, allowing an adversary to decrypt.

An issue was discovered in MediaWiki before 1.35.9, 1.36.x through 1.38.x before 1.38.5, and 1.39.x before 1.39.1. There is XSS in Wikibase date formatting via wikibase-time-precision-* fields. This allows JavaScript execution by staff/admin users who do not intentionally have the editsitejs capability.

A vulnerability, which was classified as problematic, was found in Wikisource Category Browser. This affects an unknown part of the file index.php. The manipulation of the argument lang leads to cross site scripting. It is possible to initiate the attack remotely. The patch is named 764f4e8ce3f9242637df77530c70ae8a2ec4b6a1. It is recommended to apply a patch to fix this issue. The associated identifier of this vulnerability is VDB-218415.

An issue was discovered in MediaWiki before 1.35.9, 1.36.x through 1.38.x before 1.38.5, and 1.39.x before 1.39.1. When installing with a pre-existing data directory that has weak permissions, the SQLite files are created with file mode 0644, i.e., world readable to local users. These files include credentials data.

In the GrowthExperiments extension for MediaWiki through 1.39, the growthmanagementorlist API allows blocked users (blocked in ApiManageMentorList) to enroll as mentors or edit any of their mentorship-related properties.