Cross-Site Scripting in MediaWiki GlobalWatchlist Extension

Publication date: 2026-04-07

Last updated on: 2026-04-08

Assigner: wikimedia-foundation

Description

Improper neutralization of input during web page generation ('cross-site scripting') vulnerability in The Wikimedia Foundation Mediawiki - GlobalWatchlist Extension allows Cross-Site Scripting (XSS). 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 Scores

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Meta Information

Published

2026-04-07

Last Modified

2026-04-08

Generated

2026-07-06

AI Q&A

2026-04-08

EPSS Evaluated

2026-07-05

NVD

CVE-2026-39933

EUVD

EUVD-2026-19976

Affected Vendors & Products

Vendor	Product	Version / Range
the_wikimedia_foundation	mediawiki_globalwatchlist_extension	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-79	The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Attack-Flow Graph

Executive Summary

This vulnerability is a Cross-Site Scripting (XSS) issue in the Wikimedia Foundation Mediawiki - GlobalWatchlist Extension. It occurs due to improper neutralization of input during web page generation, which means that malicious scripts can be injected and executed in the context of the affected web pages.

Impact Analysis

The vulnerability can allow attackers to execute arbitrary scripts in the context of users visiting the affected Mediawiki pages. This can lead to theft of sensitive information, session hijacking, defacement of web content, or redirection to malicious sites.

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