Medium 6.9Published Apr 7, 2026

CVE-2026-39838ProofreadPage improperly sanitizes multiline styles using Sanitizer::checkCSS

Updated under an hour ago (Oct 27, 2026, 9:00 AM ET)

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It affects Wikimedia Foundation MediaWiki - ProofreadPage Extension. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for Wikimedia Foundation MediaWiki - ProofreadPage Extension

Exploited in the last 30 days

Improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Wikimedia Foundation MediaWiki - ProofreadPage Extension allows XSS Targeting Non-Script Elements. The issue has been remediated on the `master` branch, and in the release branches for MediaWiki versions 1.43, 1.44, and 1.45.

CVSS: 6.9 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:N/SA:N
Weakness (CWE): CWE-79
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: wikimedia-foundation
NVD analysis: Awaiting Analysis
Record last updated: Apr 8, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Wikimedia Foundation MediaWiki - ProofreadPage Extension wikimedia_foundation:mediawiki_proofreadpage_extension (from the name)	before 1.43; 1.43 not affected; 1.44 not affected; 1.45 not affected	CNA record

References

References

https://phabricator.wikimedia.org/T406088
https://gerrit.wikimedia.org/r/q/Idd51e18479b32b7176b43ff74ca1c49d6bdd0628

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.