CVE-2026-39838 PUBLISHED

ProofreadPage improperly sanitizes multiline styles using Sanitizer::checkCSS

Assigner: wikimedia-foundation
Reserved: 07.04.2026 Published: 07.04.2026 Updated: 07.04.2026

Improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Wikimedia Foundation MediaWiki - ProofreadPage Extension allows XSS Targeting Non-Script Elements.This issue affects .

Metrics

CVSS 4.0

CVSS 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
CVSS Score: 6.9

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	Low	Confidentiality	Low
Attack Complexity	Low	Integrity	Low	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	Wikimedia Foundation
Product	MediaWiki - ProofreadPage Extension
Versions	Default: unaffected Version 1.43.7 is unaffected Version 1.44.4 is unaffected Version 1.45.2 is unaffected

Credits

SomeRandomDeveloper finder

References

Problem Types

CWE-79 Improper neutralization of input during web page generation ('cross-site scripting') CWE

Impacts

CAPEC-18 XSS Targeting Non-Script Elements