CVE-2026-8237: Concrete CMS 9.5.0 and below is vulnerable to IDOR in the`/ccm/frontend/conversations/message_detail` endpoint
Concrete CMS 9.5.0 and below is vulnerable to IDOR. The /ccm/frontend/conversations/messagedetail endpoint returns the full content of any conversation message. An unauthenticated attacker can enumerate all conversation messages, including messages from restricted pages, member-only areas, and the moderation queue. File attachments with download URLs are also exposed. 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 Eldudareeno for reporting.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-8237?
The severity of CVE-2026-8237 is medium with a CVSS score of 6.3.
How do I fix CVE-2026-8237?
To fix CVE-2026-8237, upgrade your Concrete CMS to version 9.5.1 or higher.
What type of vulnerability is CVE-2026-8237?
CVE-2026-8237 is an Insecure Direct Object Reference (IDOR) vulnerability.
What impact does CVE-2026-8237 have if exploited?
If exploited, CVE-2026-8237 allows an unauthenticated attacker to access and enumerate private conversation messages.
Which versions of Concrete CMS are affected by CVE-2026-8237?
CVE-2026-8237 affects Concrete CMS versions 9.5.0 and below.