An issue was discovered in the FileImporter extension for MediaWiki before 1.34.4. An attacker can import a file even when the target page is protected against "page creation" and the attacker should not be able to create it. This occurs because of a mishandled distinction between an upload restriction and a create restriction.

An attacker cannot leverage this to overwrite anything, but can leverage this to force a wiki to have a page with a disallowed title.