CVE-2026-39935: The Wikimedia Foundation Mediawiki - Campaignevents Extension

Medium severity, CVSS 6.9. EPSS: 0.5% chance of exploitation in the next 30 days.

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.

Affected products

• The Wikimedia Foundation Mediawiki - Campaignevents Extension: version 1.43 only; version 1.44 only; version 1.45 only; before 1.43 (fixed in 1.43)

Published 2026-04-07. Last modified 2026-07-21.