mediawiki uses an insecure access control. A user is able to protect a page to a higher level than they currently have permissions for.
lists.debian.org/debian-lts-announce/2021/05/msg00003.html
lists.debian.org/debian-lts-announce/2021/05/msg00006.html
lists.fedoraproject.org/archives/list/[email protected]/message/26UJGHF7LJDOCQN6A3Z4PM7PYRKENJHE/
lists.fedoraproject.org/archives/list/[email protected]/message/2OMSV7B2TCFBOCICN3B4SMQP5HVRJQIT/
phabricator.wikimedia.org/T270713
security-tracker.debian.org/tracker/CVE-2021-30152
security.gentoo.org/glsa/202107-40
www.debian.org/security/2021/dsa-4889