Cross-Site Scripting in Mediawiki CampaignEvents 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 - CampaignEvents Extension allows Cross-Site Scripting (XSS). This issue was remediated only on the `master` branch.

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-2026-39935

EUVD

EUVD-2026-19980

Affected Vendors & Products

Vendor	Product	Version / Range
the_wikimedia_foundation	mediawiki_campaignevents_extension	to 1.43.7 (inc)
the_wikimedia_foundation	mediawiki_campaignevents_extension	to 1.44.4 (inc)
the_wikimedia_foundation	mediawiki_campaignevents_extension	to 1.45.2 (inc)

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 caused by improper neutralization of input during web page generation in the Wikimedia Foundation Mediawiki CampaignEvents Extension. It affects versions 1.43.7, 1.44.4, and 1.45.2 of the extension.

Impact Analysis

The vulnerability allows attackers to inject malicious scripts into web pages generated by the CampaignEvents Extension. This can lead to unauthorized actions such as stealing user credentials, session hijacking, or executing malicious code in the context of the affected website.

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