Description
An issue was discovered in the CheckUser extension for MediaWiki through 1.35.2. MediaWiki usernames with trailing whitespace could be stored in the cu_log database table such that denial of service occurred for certain CheckUser extension pages and functionality. For example, the attacker could turn off Special:CheckUserLog and thus interfere with usage tracking.
References
- https://phabricator.wikimedia.org/T275669
- https://gerrit.wikimedia.org/r/c/mediawiki/extensions/CheckUser/+/667023
- https://gerrit.wikimedia.org/r/c/mediawiki/extensions/CheckUser/+/667024
- https://gerrit.wikimedia.org/r/c/mediawiki/extensions/CheckUser/+/667025
- https://gerrit.wikimedia.org/r/c/mediawiki/extensions/CheckUser/+/667027
- https://gerrit.wikimedia.org/r/c/mediawiki/extensions/CheckUser/+/666963
- https://gerrit.wikimedia.org/r/c/mediawiki/extensions/CheckUser/+/666964