CVE-2019-18611: Mediawiki Checkuser

Medium severity, CVSS 6.5. EPSS: 0.9% chance of exploitation in the next 30 days.

An issue was discovered in the CheckUser extension through 1.34 for MediaWiki. Certain sensitive information within oversighted edit summaries made available via the MediaWiki API was potentially visible to users with various levels of access to this extension. Said users should not have been able to view these oversighted edit summaries via the MediaWiki API.

Affected products

• Mediawiki Checkuser: up to and including 1.34

Published 2019-10-29. Last modified 2026-06-17.