CVE-2021-39325: Optinmonster

Medium severity, CVSS 6.1. EPSS: 0.9% chance of exploitation in the next 30 days.

The OptinMonster WordPress plugin is vulnerable to Reflected Cross-Site Scripting due to insufficient input validation in the load_previews function found in the ~/OMAPI/Output.php file which allows attackers to inject arbitrary web scripts, in versions up to and including 2.6.0.

Affected products

• Optinmonster Optinmonster: up to and including 2.6.0

Published 2021-09-20. Last modified 2026-06-17.