In MediaWiki before 1.31.10 and 1.32.x through 1.34.x before 1.34.4, Special:UserRights exposes the existence of hidden users.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-25813
Reference (s):
- https://lists.wikimedia.org/pipermail/mediawiki-l/2020-September/048480.html
- FEDORA:FEDORA-2020-a4802c53d9
- URL: https://lists.fedoraproject.org/archives/list/[email protected]/message/RTTPZ7XMDS66I442OLLHXBDNP2LCBJU6/
- https://lists.wikimedia.org/pipermail/mediawiki-l/2020-September/048488.html
- https://meta.wikimedia.org/wiki/Special:UserRights