CVE-2026-7888
Published:June 03, 2026
Updated:June 07, 2026
Concrete CMS below 9.5.2 is vulnerable to PHP Object Injection via unserialize() calls in the Workflow, Form block, and File/Set components that lack the allowed_classes restriction. An unauthenticated attacker may trigger arbitrary PHP object instantiation if a malicious serialized payload has been placed in the database. Thanks XananasX7 and Sanjorn Keeratirungsan (dizconnect) for both independently reporting. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 8.4 with vector CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N.
Affected Packages
https://github.com/concretecms/concretecms.git (GITHUB):
Affected version(s) >=5.7.0 <9.5.2Fix Suggestion:
Update to version 9.5.2concrete5/concrete5 (PHP):
Affected version(s) >=dev-allow-install-php-8.2 <9.5.2Fix Suggestion:
Update to version 9.5.2Related Resources (1)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.4
Attack Vector
LOCAL
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
HIGH
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.7
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
Deserialization of Untrusted Data
EPSS
Base Score:
0.02