CVE-2026-8237

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

0.6% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2026-05-21 22:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-07-23 11:10 UTC Last updatedMost recent change to the record

Details

Published

2026-05-21 22:16 UTC

Last modified

2026-07-23 11:10 UTC

Exploit probability

0.6% · EPSS, next 30 days

Weakness

CWE-862 · Missing authorization

Record status

Analyzed

Affected

• Concretecms Concrete Cms < 9.5.1

Attack profile CVSS 4.0 · 6.3

Attack vector

Network

Complexity

Low

Attack requirements

Present

Privileges needed

None

User interaction

None

Confidentiality

Low

Integrity

None

Availability

None