CVSS7.2
Severityhigh
WeaknessCWE-502
ExploitedNot in CISA KEV
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
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 "true" is evaluated as a strict PHP Boolean(true). This bypass allows the attacker to inject a malicious serialized payload into the block's filterFields database column. The payload will subsequently be executed when the block's data is