CVE-2021-39186

Name: CVE-2021-39186
Creator: NVD / NIST
Published: 2021-09-01T21:15:07.263+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 1.01%

Last modified Jun 17, 2026

CVE-2021-39186 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. GlobalNewFiles is a MediaWiki extension maintained by Miraheze. Prior to commit number cee254e1b158cdb0ddbea716b1d3edc31fa4fb5d, the username column of the GlobalNewFiles special page is vulnerable to a stored XSS. EPSS estimates a 1.01% chance of exploitation in the next 30 days.

Description

GlobalNewFiles is a MediaWiki extension maintained by Miraheze. Prior to commit number cee254e1b158cdb0ddbea716b1d3edc31fa4fb5d, the username column of the GlobalNewFiles special page is vulnerable to a stored XSS. Commit number cee254e1b158cdb0ddbea716b1d3edc31fa4fb5d contains a patch. As a workaround, one may disallow <,> (or other characters required to insert html/js) from being used in account names so an XSS is not possible.

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

1.01%

58.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-20

Affected Software

Vendor	Product	Versions
Miraheze	Globalnewfiles	< 2021-09-01

References

https://github.com/miraheze/GlobalNewFiles/commit/cee254e1b158cdb0ddbea716b1d3edc31fa4fb5dPatch, Third Party Advisory
https://github.com/miraheze/GlobalNewFiles/security/advisories/GHSA-57p5-hqjq-h7vgThird Party Advisory
https://phabricator.miraheze.org/T7935Exploit, Third Party Advisory
https://github.com/miraheze/GlobalNewFiles/commit/cee254e1b158cdb0ddbea716b1d3edc31fa4fb5dPatch, Third Party Advisory
https://github.com/miraheze/GlobalNewFiles/security/advisories/GHSA-57p5-hqjq-h7vgThird Party Advisory
https://phabricator.miraheze.org/T7935Exploit, Third Party Advisory

Timeline

Published: Sep 1, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-39186?

How severe is CVE-2021-39186?

CVE-2021-39186 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 1.01% probability of exploitation in the next 30 days.

How do I fix CVE-2021-39186?

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-2021-39186?

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

Scan your code now

Source: NVD / NIST