CVE-2026-65639: Configserver Security & Firewall

Critical severity, CVSS 9.5. EPSS: 1.4% chance of exploitation in the next 30 days.

OS command injection in the advanced-rule parser of ConfigServer Security & Firewall allows a remote attacker who controls a configured allow/deny feed to execute arbitrary commands as root, due to insufficient validation of feed-supplied rule data. The vulnerability affects versions of the software originally distributed by ConfigServer, as well as versions of the WebPros-maintained fork that contain the vulnerable code. WebPros has addressed the vulnerability in version 16.30. Other forks or independently maintained versions of ConfigServer Security & Firewall (CSF) may also be affected and should be evaluated independently.

Affected products

• Configserver Configserver Security & Firewall: from 2.15
• WebPros Configserver Security & Firewall: from 2.15, before 16.30 (fixed in 16.30)

Published 2026-09-10. Last modified 2026-09-10.