CVE-2026-39838mediumCWE-79

CVE-2026-39838: medium-severity vulnerability in Wikimedia Foundation MediaWiki - ProofreadPage…

ProofreadPage improperly sanitizes multiline styles using Sanitizer::checkCSS

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13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 6.9epss 0.4%
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:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:N/SA:N
Affected products
Wikimedia Foundation · MediaWiki - ProofreadPage Extension
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CVE-2026-0670MEDIUMStored XSS through a system message and a user-provided parameter in ProofreadPageEPSS 0.2%