CVE-2020-13978: Monstra CMS

High severity, CVSS 7.2. EPSS: 1.3% chance of exploitation in the next 30 days.

Monstra CMS 3.0.4 allows an attacker, who already has administrative access to modify .chunk.php files on the Edit Chunk screen, to execute arbitrary OS commands via the Theme Module by visiting the admin/index.php?id=themes&action=edit_chunk URI. NOTE: there is no indication that the Edit Chunk feature was intended to prevent an administrator from using PHP's exec feature

Affected products

• Monstra Monstra CMS: version 3.0.4 only

Published 2020-06-09. Last modified 2026-06-17.