CVE-2021-39357: ZEEN101 Leaky Paywall

Medium severity, CVSS 4.8. EPSS: 0.9% chance of exploitation in the next 30 days.

The Leaky Paywall WordPress plugin is vulnerable to Stored Cross-Site Scripting due to insufficient input validation and sanitization via the ~/class.php file which allowed attackers with administrative user access to inject arbitrary web scripts, in versions up to and including 4.16.5. This affects multi-site installations where unfiltered_html is disabled for administrators, and sites where unfiltered_html is disabled.

Affected products

• ZEEN101 Leaky Paywall: up to and including 4.16.5

Published 2021-10-21. Last modified 2026-06-17.