CVE-2026-8237
Analyzed Analyzed - Analysis Complete
Insecure Direct Object Reference in Concrete CMS

Publication date: 2026-05-21

Last updated on: 2026-05-26

Assigner: ConcreteCMS

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.
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Meta Information
Published
2026-05-21
Last Modified
2026-05-26
Generated
2026-06-11
AI Q&A
2026-05-22
EPSS Evaluated
2026-06-10
NVD
CVE-2026-8237
EUVD
EUVD-2026-31352
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
concretecms concrete_cms to 9.5.1 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-862 The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
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Executive Summary

This vulnerability is an Insecure Direct Object Reference (IDOR) in Concrete CMS version 9.5.0 and below. It occurs at the /ccm/frontend/conversations/message_detail endpoint, which returns the full content of any conversation message.

An unauthenticated attacker can exploit this flaw to enumerate all conversation messages, including those from restricted pages, member-only areas, and the moderation queue. Additionally, file attachments with download URLs are exposed through this vulnerability.

Impact Analysis

This vulnerability allows an unauthenticated attacker to access sensitive conversation messages and file attachments that should be restricted. This can lead to unauthorized disclosure of private or confidential information.

Because the attacker does not need to be authenticated, the risk of data leakage is significant, potentially exposing user communications, internal discussions, or sensitive files to unauthorized parties.

Compliance Impact

This vulnerability allows an unauthenticated attacker to access full content of any conversation message, including those from restricted pages, member-only areas, and the moderation queue, as well as file attachments with download URLs.

Such unauthorized access to potentially sensitive or personal information could lead to non-compliance with data protection regulations like GDPR and HIPAA, which require protection of personal and sensitive data from unauthorized disclosure.

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