CVE-2021-40102: Concretecms Concrete CMS

Critical severity, CVSS 9.1. EPSS: 1.3% chance of exploitation in the next 30 days.

An issue was discovered in Concrete CMS through 8.5.5. Arbitrary File deletion can occur via PHAR deserialization in is_dir (PHP Object Injection associated with the __wakeup magic method).

Affected products

• Concretecms Concrete CMS: up to and including 8.5.5

Published 2021-09-24. Last modified 2026-06-17.