CVE-2021-30159: Medium severity mediawiki vulnerability
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(READLATEST) 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.
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is the severity of CVE-2021-30159?
The severity of CVE-2021-30159 is considered to be moderate due to the potential for unauthorized page deletions under specific conditions.
How do I fix CVE-2021-30159?
To fix CVE-2021-30159, update MediaWiki to a version greater than 1.31.12 or 1.35.2 as appropriate for your system.
Which versions of MediaWiki are affected by CVE-2021-30159?
CVE-2021-30159 affects MediaWiki versions before 1.31.12 and versions between 1.32.0 and 1.35.2 inclusive.
What are the risks of CVE-2021-30159 if left unpatched?
If left unpatched, CVE-2021-30159 could allow users to bypass restrictions and delete pages unexpectedly in certain scenarios.
What platforms are vulnerable to CVE-2021-30159?
CVE-2021-30159 affects users on Debian and Fedora platforms running the specified vulnerable versions of MediaWiki.