CVE-2021-31551

Name: CVE-2021-31551
Creator: NVD / NIST
Published: 2021-04-22T03:15:08.13+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.90%

Last modified Jun 17, 2026

CVE-2021-31551 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. An issue was discovered in the PageForms extension for MediaWiki through 1.35.2. Crafted payloads for Token-related query parameters allowed for XSS on certain PageForms-managed MediaWiki pages.. EPSS estimates a 0.90% chance of exploitation in the next 30 days.

Description

An issue was discovered in the PageForms extension for MediaWiki through 1.35.2. Crafted payloads for Token-related query parameters allowed for XSS on certain PageForms-managed MediaWiki pages.

Metrics

CVSS 3.1

6.1/10

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

EPSS Probability

0.90%

54.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Mediawiki	Mediawiki	<= 1.35.2

References

https://gerrit.wikimedia.org/r/q/I20b63bd38779d2ccbe2d86f9879df85ca3b685f6Issue Tracking, Third Party Advisory
https://gerrit.wikimedia.org/r/q/I5e0abbc2f80e6bda255b3b32a4df39a7fe7d3793Issue Tracking, Third Party Advisory
https://gerrit.wikimedia.org/r/q/Ibe68b070ee791cd0c8e7f50eb04ac4e066b1512cIssue Tracking, Third Party Advisory
https://phabricator.wikimedia.org/T259433Third Party Advisory
https://gerrit.wikimedia.org/r/q/I20b63bd38779d2ccbe2d86f9879df85ca3b685f6Issue Tracking, Third Party Advisory
https://gerrit.wikimedia.org/r/q/I5e0abbc2f80e6bda255b3b32a4df39a7fe7d3793Issue Tracking, Third Party Advisory
https://gerrit.wikimedia.org/r/q/Ibe68b070ee791cd0c8e7f50eb04ac4e066b1512cIssue Tracking, Third Party Advisory
https://phabricator.wikimedia.org/T259433Third Party Advisory

Timeline

Published: Apr 22, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-31551?

An issue was discovered in the PageForms extension for MediaWiki through 1.35.2. Crafted payloads for Token-related query parameters allowed for XSS on certain PageForms-managed MediaWiki pages.

How severe is CVE-2021-31551?

CVE-2021-31551 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.90% probability of exploitation in the next 30 days.

How do I fix CVE-2021-31551?

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-2021-31551?

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

Scan your code now

Source: NVD / NIST