CVE-2020-35479: Debian Linux

Medium severity, CVSS 6.1. EPSS: 1.5% chance of exploitation in the next 30 days.

MediaWiki before 1.35.1 allows XSS via BlockLogFormatter.php. Language::translateBlockExpiry itself does not escape in all code paths. For example, the return of Language::userTimeAndDate is is always unsafe for HTML in a month value. This affects MediaWiki 1.12.0 and later.

Affected products

• Debian Debian Linux: version 9.0 only; version 10.0 only
• Fedoraproject Fedora: version 33 only
• Mediawiki Mediawiki: from 1.12.0, before 1.35.1 (fixed in 1.35.1)

Published 2020-12-18. Last modified 2026-06-17.