CVE-2026-8237

Concrete CMS 9.5.0 and below is vulnerable to IDOR in the`/ccm/frontend/conversations/message_detail` endpoint

State: Published
Severity: 6.3 Medium
Published: May 21, 2026
Updated: May 22, 2026
Reserved: May 9, 2026

Description

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, 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.

Scores

CVSS	Score	Vector	Source
4.0	6.3 Medium	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	ConcreteCMS

Weaknesses

CWE-862

Affected Products

Product	Versions
Concrete CMSConcrete CMS	5.0 through 9.5.0Affected

References

https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notesrelease-notes

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