Auth bypass in Concrete Cms

CVE-2026-8237

Concrete CMS 9.5.0 and below is vulnerable to IDOR. The `/ccm/frontend/conversations/message_detail` endpoint returns the full content of any conversation message. An unauthenticated attacker can enumerate all conversation messages, includ…

Vulnerability class: Broken Access Control

EPSS: 0.000 (14.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-8237?
CVE-2026-8237 is a medium-severity vulnerability in Concrete Cms, classified under Missing Authorization. CVSS score: 5.3/10. Published 2026-05-21.
How severe is CVE-2026-8237?
Medium severity. CVSS v3 base score is 5.3 out of 10.