CVE-2021-42042

Name: CVE-2021-42042
Creator: NVD / NIST
Published: 2021-10-06T21:15:07.297+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.8/10EPSS 0.53%

Last modified Jun 17, 2026

CVE-2021-42042 is a medium-severity vulnerability rated 4.8/10 on the CVSS scale. An issue was discovered in SpecialEditGrowthConfig in the GrowthExperiments extension in MediaWiki through 1.36.2. The growthexperiments-edit-config-error-invalid-title MediaWiki message was not being properly sanitized and allowed for the injection and execution of HTML and JavaScript.. EPSS estimates a 0.53% chance of exploitation in the next 30 days.

Description

An issue was discovered in SpecialEditGrowthConfig in the GrowthExperiments extension in MediaWiki through 1.36.2. The growthexperiments-edit-config-error-invalid-title MediaWiki message was not being properly sanitized and allowed for the injection and execution of HTML and JavaScript.

Metrics

CVSS 3.1

4.8/10

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

EPSS Probability

0.53%

40.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Mediawiki	Mediawiki	<= 1.36.2

References

https://gerrit.wikimedia.org/r/q/Ibeb13d032ca044af53f6b2334e27b6b97b6f4e9fPatch, Vendor Advisory
https://phabricator.wikimedia.org/T290692Issue Tracking, Patch, Vendor Advisory
https://gerrit.wikimedia.org/r/q/Ibeb13d032ca044af53f6b2334e27b6b97b6f4e9fPatch, Vendor Advisory
https://phabricator.wikimedia.org/T290692Issue Tracking, Patch, Vendor Advisory

Timeline

Published: Oct 6, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-42042?

How severe is CVE-2021-42042?

CVE-2021-42042 has a CVSS score of 4.8/10 (MEDIUM severity). The EPSS model estimates a 0.53% probability of exploitation in the next 30 days.

How do I fix CVE-2021-42042?

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-2021-42042?

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

Scan your code now

Source: NVD / NIST