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.
https://www.debian.org/security/2023/dsa-5520
https://phabricator.wikimedia.org/T333050
https://lists.debian.org/debian-lts-announce/2023/11/msg00027.html