An issue was discovered in the CommentBox extension for MediaWiki through 1.35.2. Via crafted configuration variables, a malicious actor could introduce XSS payloads into various layers.

An issue was discovered in the AbuseFilter extension for MediaWiki through 1.35.2. The Special:AbuseFilter/examine form allowed for the disclosure of suppressed MediaWiki usernames to unprivileged users.

An issue was discovered in the AbuseFilter extension for MediaWiki through 1.35.2. A MediaWiki user who is partially blocked or was unsuccessfully blocked could bypass AbuseFilter and have their edits completed.

An issue was discovered in the AbuseFilter extension for MediaWiki through 1.35.2. Its AbuseFilterCheckMatch API reveals suppressed edits and usernames to unprivileged users through the iteration of crafted AbuseFilter rules.

An issue was discovered in the AbuseFilter extension for MediaWiki through 1.35.2. It incorrectly logged sensitive suppression deletions, which should not have been visible to users with access to view AbuseFilter log data.

An issue was discovered in the AbuseFilter extension for MediaWiki through 1.35.2. The page_recent_contributors leaked the existence of certain deleted MediaWiki usernames, related to rev_deleted.

The API in the Push extension for MediaWiki through 1.35 used cleartext for ApiPush credentials, allowing for potential information disclosure.

The API in the Push extension for MediaWiki through 1.35 did not require an edit token in ApiPushBase.php and therefore facilitated a CSRF attack.

An issue was discovered in the PushToWatch extension for MediaWiki through 1.35.1. The primary form did not implement an anti-CSRF token and therefore was completely vulnerable to CSRF attacks against onSkinAddFooterLinks in PushToWatch.php.

An issue was discovered in the Widgets extension for MediaWiki through 1.35.1. Any user with the ability to edit pages within the Widgets namespace could call any static function within any class (defined within PHP or MediaWiki) via a crafted HTML comment, related to a Smarty template. For example, a person in the Widget Editors group could use \MediaWiki\Shell\Shell::command within a comment.

An issue was discovered in the SecurePoll extension for MediaWiki through 1.35.1. The non-admin vote list contains a full vote timestamp, which may provide unintended clues about how a voting process unfolded.

An issue was discovered in the CasAuth extension for MediaWiki through 1.35.1. Due to improper username validation, it allowed user impersonation with trivial manipulations of certain characters within a given username. An ordinary user may be able to login as a "bureaucrat user" who has a similar username, as demonstrated by usernames that differ only in (1) bidirectional override symbols or (2) blank space.

An issue was discovered in the GlobalUsage extension for MediaWiki through 1.35.1. SpecialGlobalUsage.php calls WikiMap::makeForeignLink unsafely. The $page variable within the formatItem function was not being properly escaped, allowing for XSS under certain conditions.

An issue was discovered in MediaWiki before 1.35.1. Missing users (accounts that don't exist) and hidden users (accounts that have been explicitly hidden due to being abusive, or similar) that the viewer cannot see are handled differently, exposing sensitive information about the hidden status to unprivileged viewers. This exists on various code paths.

MediaWiki before 1.35.1 allows XSS via BlockLogFormatter.php. Language::translateBlockExpiry itself does not escape in all code paths. For example, the return of Language::userTimeAndDate is is always unsafe for HTML in a month value. This affects MediaWiki 1.12.0 and later.

MediaWiki before 1.35.1 blocks legitimate attempts to hide log entries in some situations. If one sets MediaWiki:Mainpage to Special:MyLanguage/Main Page, visits a log entry on Special:Log, and toggles the "Change visibility of selected log entries" checkbox (or a tags checkbox) next to it, there is a redirection to the main page's action=historysubmit (instead of the desired behavior in which a revision-deletion form appears).

In MediaWiki before 1.35.1, the messages userrights-expiry-current and userrights-expiry-none can contain raw HTML. XSS can happen when a user visits Special:UserRights but does not have rights to change all userrights, and the table on the left side has unchangeable groups in it. (The right column with the changeable groups is not affected and is escaped correctly.)

In MediaWiki before 1.35.1, the combination of Html::rawElement and Message::text leads to XSS because the definition of MediaWiki:recentchanges-legend-watchlistexpiry can be changed onwiki so that the output is raw HTML.

The PollNY extension for MediaWiki through 1.35 allows XSS via an answer option for a poll question, entered during Special:CreatePoll or Special:UpdatePoll.

includes/CologneBlueTemplate.php in the CologneBlue skin for MediaWiki through 1.35 allows XSS via a qbfind message supplied by an administrator.