CVE-2026-39838

MEDIUM

ProofreadPage improperly sanitizes multiline styles using Sanitizer::checkCSS

Title source: cna

Description

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.

References (2)

Core 2

Core References

https://phabricator.wikimedia.org/T406088

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

Scores

CVSS v4 6.9

EPSS 0.0040

EPSS Percentile 31.8%

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CISA SSVC

Vulnrichment

Exploitation poc

Automatable no

Technical Impact partial

Details

CWE

CWE-79

Status published

Products (7)

Wikimedia Foundation/MediaWiki - ProofreadPage Extension < 1.43

Wikimedia Foundation/MediaWiki - ProofreadPage Extension 1.43

Wikimedia Foundation/MediaWiki - ProofreadPage Extension 1.43.7

Wikimedia Foundation/MediaWiki - ProofreadPage Extension 1.44

Wikimedia Foundation/MediaWiki - ProofreadPage Extension 1.44.4

Wikimedia Foundation/MediaWiki - ProofreadPage Extension 1.45

Wikimedia Foundation/MediaWiki - ProofreadPage Extension 1.45.2

Published Apr 07, 2026

Tracked Since Apr 08, 2026