CVE-2025-4369: Papin Companion Auto Update

Medium severity, CVSS 5.5. EPSS: 0.3% chance of exploitation in the next 30 days.

The Companion Auto Update plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘update_delay_days’ parameter in all versions up to, and including, 3.9.2 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level access, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.

Affected products

• Papin Companion Auto Update: up to and including 3.9.2

Published 2025-07-15. Last modified 2026-06-17.