What is CVE-2021-46150?

CVE-2021-46150 is a medium-severity vulnerability in MediaWiki, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2022-01-10.

How severe is CVE-2021-46150?

Medium severity. CVSS v3 base score is 4.8 out of 10.

XSS in MediaWiki

CVE-2021-46150

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. Special:CheckUserLog allows CheckUser XSS because of date mishandling, as demonstrated by an XSS payload in MediaWiki:October.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2022-01-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.006 (49.0th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 49.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

MediaWiki

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

phabricator.wikimedia.org/T292795 (Exploit, Third Party Advisory)
gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/extensions/CheckUser/+/79c2c49… (Third Party Advisory)

Frequently asked questions

What is CVE-2021-46150?: CVE-2021-46150 is a medium-severity vulnerability in MediaWiki, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2022-01-10.
How severe is CVE-2021-46150?: Medium severity. CVSS v3 base score is 4.8 out of 10.