CVE-2021-30458

Name: CVE-2021-30458
Creator: NVD / NIST
Published: 2021-04-09T07:15:16.34+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.98%

Last modified Jun 17, 2026

CVE-2021-30458 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. An issue was discovered in Wikimedia Parsoid before 0.11.1 and 0.12.x before 0.12.2. An attacker can send crafted wikitext that Utils/WTUtils.php will transform by using a <meta> tag, bypassing sanitization steps, and potentially allowing for XSS.. EPSS estimates a 0.98% chance of exploitation in the next 30 days.

Description

An issue was discovered in Wikimedia Parsoid before 0.11.1 and 0.12.x before 0.12.2. An attacker can send crafted wikitext that Utils/WTUtils.php will transform by using a <meta> tag, bypassing sanitization steps, and potentially allowing for XSS.

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

0.98%

57.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Wikimedia	Parsoid	< 0.11.1
Wikimedia	Parsoid	>= 0.12.0, < 0.12.2

References

https://phabricator.wikimedia.org/T279451Issue Tracking, Vendor Advisory
https://security.gentoo.org/glsa/202107-40Third Party Advisory
https://www.mediawiki.org/wiki/ParsoidVendor Advisory
https://phabricator.wikimedia.org/T279451Issue Tracking, Vendor Advisory
https://security.gentoo.org/glsa/202107-40Third Party Advisory
https://www.mediawiki.org/wiki/ParsoidVendor Advisory

Timeline

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

Frequently Asked Questions

What is CVE-2021-30458?

How severe is CVE-2021-30458?

CVE-2021-30458 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.98% probability of exploitation in the next 30 days.

How do I fix CVE-2021-30458?

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-2021-30458?

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

Scan your code now

Source: NVD / NIST