CVE-2026-8239

Concrete CMS 9.5.0 and below is vulnerable to IDOR. The '/ccm/frontend/conversations/get_rating' endpoint confirms existence and returns rating score for any message by ID. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 6.3 with Vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Tristan Madani for reporting.

Affected products

Concrete Cms

Concretecms Concrete Cms

< 9.5.1

Fix

Available

CVSS 4.0

6.3 MEDIUM

CVSS 3.1

5.3 MEDIUM

EPSS

0.2% (9th percentile)

Weakness

CWE-862

NVD status

Analyzed

Published

2026-05-21

Attack patterns

CAPEC-122

Entry point

message_id query param

Path

ccm/frontend/conversations/get_rating