CVE-2021-30159

Public Exploit

Description

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.

4.3

CVSS

Severity: Medium

CVSS 3.1 •

CVSS 2.0 •

EPSS 0.57%

Vendor Advisory debian.org Vendor Advisory fedoraproject.org Vendor Advisory fedoraproject.org Vendor Advisory gentoo.org Vendor Advisory wikimedia.org

Affected: n/a n/a

References

Link	Tags
https://phabricator.wikimedia.org/T272386	exploit patch vendor advisory
https://www.debian.org/security/2021/dsa-4889	third party advisory vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/26UJGHF7LJDOCQN6A3Z4PM7PYRKENJHE/	vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2OMSV7B2TCFBOCICN3B4SMQP5HVRJQIT/	vendor advisory
https://lists.debian.org/debian-lts-announce/2021/05/msg00003.html	third party advisory mailing list
https://lists.debian.org/debian-lts-announce/2021/05/msg00006.html	third party advisory mailing list
https://security.gentoo.org/glsa/202107-40	third party advisory vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-30159?: CVE-2021-30159 has been scored as a medium severity vulnerability.
How to fix CVE-2021-30159?: To fix CVE-2021-30159, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-30159 being actively exploited in the wild?: It is possible that CVE-2021-30159 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.