What is CVE-2021-42046?

CVE-2021-42046 is a medium-severity vulnerability in MediaWiki, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2022-09-29.

How severe is CVE-2021-42046?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in MediaWiki

CVE-2021-42046

An issue was discovered in the GlobalWatchlist extension in MediaWiki through 1.36.2. The rev-deleted-user and ntimes messages were not properly escaped and allowed for users to inject HTML and JavaScript.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2022-09-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.009 (57.0th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 57th percentile — 57.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

MediaWiki

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

phabricator.wikimedia.org/T286385 (Vendor Advisory)
gerrit.wikimedia.org/r/q/Ib7f9b009730fe0df283cec1169f84c7a83a58b1d (Patch, Vendor Advisory)
gerrit.wikimedia.org/r/q/Id2204fb5afe591d63764466de35ac0aaa5999983 (Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2021-42046?: CVE-2021-42046 is a medium-severity vulnerability in MediaWiki, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2022-09-29.
How severe is CVE-2021-42046?: Medium severity. CVSS v3 base score is 6.1 out of 10.