Report: CVE-2026-8135 - Concrete CMS 9.5.0 and below is vulnerable to RCE due to insecure deserialization

Report: CVE-2026-8135 - Concrete CMS 9.5.0 and below is vulnerable to RCE due to insecure deserialization

CVE ID :CVE-2026-8135 Published : May 21, 2026, 8:16 p.m. | 45 minutes ago Description :Concrete CMS 9.5.0 and below is vulnerable to Remote Code Execution due to insecure deserialization occurring in the ExpressEntryList block controller. An rogue administrator with privileges to add blocks to an area can bypass the intended protection mechanism (_fromCIF === true), which normally restricts malicious inputs over form POST requests, by leveraging the REST API functionality. Because the REST API parses requests using json_decode(), the string

CVE Details

Published
May 21, 2026
Impact: Remote Code Execution