CVE-2021-30159

An issue was discovered in MediaWiki before 1.31.12 and 1.32.x through
1.35.x before 1.35.2. Users can bypass intended restrictions on deleting
pages in certain “fast double move” situations.
MovePage::isValidMoveTarget() uses FOR UPDATE, but it’s only called if
Title::getArticleID() returns non-zero with no special flags. Next,
MovePage::moveToInternal() will delete the page if
getArticleID(READ_LATEST) is non-zero. Therefore, if the page is missing in
the replica DB, isValidMove() will return true, and then moveToInternal()
will unconditionally delete the page if it can be found in the master.