CVE-2026-39838CWE-79

ProofreadPage improperly sanitizes multiline styles using Sanitizer::checkCSS

Medium · published April 7, 2026

CVSS v4.0
6.9
EPSS
0%
Percentile
38.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
6.9 · MEDIUM
Vector
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
EPSS
0.00453 · 38.4th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-04-07T19:17Z
EPSS history
Timeline
  • 07 APR 19:17Z
    ProofreadPage improperly sanitizes multiline styles using Sanitizer::checkCSS
    cvelistv5