In MediaWiki before 1.31.15, 1.32.x through 1.35.x before 1.35.3, and 1.36.x before 1.36.1, bots have certain unintended API access. When a bot account has a "sitewide block" applied, it is able to still "purge" pages through the MediaWiki Action API (which a "sitewide block" should have prevented).
https://www.debian.org/security/2021/dsa-4979
https://security.gentoo.org/glsa/202107-40
https://phabricator.wikimedia.org/T280226
https://lists.debian.org/debian-lts-announce/2021/10/msg00003.html