CVE-2021-44857

Name: CVE-2021-44857
Creator: NVD / NIST
Published: 2021-12-17T04:15:39.137+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.87%

Last modified Jun 17, 2026

CVE-2021-44857 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. An issue was discovered in MediaWiki before 1.35.5, 1.36.x before 1.36.3, and 1.37.x before 1.37.1. It is possible to use action=mcrundo followed by action=mcrrestore to replace the content of any arbitrary page (that the user doesn't have edit rights for). EPSS estimates a 0.87% chance of exploitation in the next 30 days.

Description

An issue was discovered in MediaWiki before 1.35.5, 1.36.x before 1.36.3, and 1.37.x before 1.37.1. It is possible to use action=mcrundo followed by action=mcrrestore to replace the content of any arbitrary page (that the user doesn't have edit rights for). This applies to any public wiki, or a private wiki that has at least one page set in $wgWhitelistRead.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

0.87%

54.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-862

Affected Software

Vendor	Product	Versions
Mediawiki	Mediawiki	< 1.35.5
Mediawiki	Mediawiki	>= 1.36.0, < 1.36.3
Mediawiki	Mediawiki	>= 1.37.0, < 1.37.1

References

https://phabricator.wikimedia.org/T297322Third Party Advisory
https://security.gentoo.org/glsa/202305-24
https://www.mediawiki.org/wiki/2021-12_security_release/FAQVendor Advisory
https://phabricator.wikimedia.org/T297322Third Party Advisory
https://security.gentoo.org/glsa/202305-24
https://www.mediawiki.org/wiki/2021-12_security_release/FAQVendor Advisory

Timeline

Published: Dec 17, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-44857?

How severe is CVE-2021-44857?

CVE-2021-44857 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.87% probability of exploitation in the next 30 days.

How do I fix CVE-2021-44857?

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-2021-44857?

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

Scan your code now

Source: NVD / NIST