CVE-2026-3452: Concretecms Concrete CMS

High severity, CVSS 7.2. EPSS: 0.9% chance of exploitation in the next 30 days.

Concrete CMS below version 9.4.8 is vulnerable to Remote Code Execution by stored PHP object injection into the Express Entry List block via the columns parameter. An authenticated administrator can store attacker-controlled serialized data in block configuration fields that are later passed to unserialize() without class restrictions or integrity checks. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 8.9 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H. Thanks YJK ( @YJK0805 https://hackerone.com/yjk0805 ) of ZUSO ART https://zuso.ai/  for reporting.

Affected products

• Concretecms Concrete CMS: before 9.4.8 (fixed in 9.4.8)

Published 2026-03-04. Last modified 2026-06-17.