CVE-2021-40099: Concretecms Concrete CMS

High severity, CVSS 7.2. EPSS: 2.1% chance of exploitation in the next 30 days.

An issue was discovered in Concrete CMS through 8.5.5. Fetching the update json scheme over HTTP leads to remote code execution.

Affected products

• Concretecms Concrete CMS: up to and including 8.5.5

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