CVE-2021-30159

Name: CVE-2021-30159
Creator: NVD / NIST
Published: 2021-04-09T07:15:16.277+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.3/10EPSS 1.56%

Last modified Jun 17, 2026

CVE-2021-30159 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. 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. EPSS estimates a 1.56% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

4.3/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS Probability

1.56%

72.1th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Mediawiki	Mediawiki	< 1.31.12
Mediawiki	Mediawiki	>= 1.32.0, < 1.35.2
Debian	Debian Linux	9.0
Debian	Debian Linux	10.0
Fedoraproject	Fedora	33
Fedoraproject	Fedora	34

References

https://lists.debian.org/debian-lts-announce/2021/05/msg00003.htmlThird Party Advisory
https://lists.debian.org/debian-lts-announce/2021/05/msg00006.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/26UJGHF7LJDOCQN6A3Z4PM7PYRKENJHE/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2OMSV7B2TCFBOCICN3B4SMQP5HVRJQIT/
https://phabricator.wikimedia.org/T272386Exploit, Patch, Vendor Advisory
https://security.gentoo.org/glsa/202107-40Third Party Advisory
https://www.debian.org/security/2021/dsa-4889Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/05/msg00003.htmlThird Party Advisory
https://lists.debian.org/debian-lts-announce/2021/05/msg00006.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/26UJGHF7LJDOCQN6A3Z4PM7PYRKENJHE/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2OMSV7B2TCFBOCICN3B4SMQP5HVRJQIT/
https://phabricator.wikimedia.org/T272386Exploit, Patch, Vendor Advisory
https://security.gentoo.org/glsa/202107-40Third Party Advisory
https://www.debian.org/security/2021/dsa-4889Third Party Advisory

Timeline

Published: Apr 9, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-30159?

How severe is CVE-2021-30159?

CVE-2021-30159 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 1.56% probability of exploitation in the next 30 days.

How do I fix CVE-2021-30159?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-30159?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST