CVE-2021-39318: h5p-Css-Editor Project h5p-Css-Editor

Medium severity, CVSS 6.1. EPSS: 0.8% chance of exploitation in the next 30 days.

The H5P CSS Editor WordPress plugin is vulnerable to Reflected Cross-Site Scripting via the h5p-css-file parameter found in the ~/h5p-css-editor.php file which allows attackers to inject arbitrary web scripts, in versions up to and including 1.0.

Affected products

• h5p-Css-Editor Project h5p-Css-Editor: up to and including 1.0

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