CVE-2021-41836: Conva Fathom Analytics

Medium severity, CVSS 4.8. EPSS: 0.6% chance of exploitation in the next 30 days.

The Fathom Analytics WordPress plugin is vulnerable to Stored Cross-Site Scripting due to insufficient input validation and escaping via the $site_id parameter found in the ~/fathom-analytics.php file which allowed attackers with administrative user access to inject arbitrary web scripts, in versions up to and including 3.0.4. This affects multi-site installations where unfiltered_html is disabled for administrators, and sites where unfiltered_html is disabled.

Affected products

• Conva Fathom Analytics: up to and including 3.0.4

Published 2021-12-14. Last modified 2026-06-17.