Description
Concrete CMS 9.2.0 to 9.5.2 contain a missing authorization vulnerability in the REST API Groups list endpoint. The listGroups() method in concrete/src/Api/Controller/Groups.php registers a permissions checker callback that unconditionally returns true, so no per-object (tree node) authorization is enforced when the group collection is returned. An authenticated user whose API token carries the groups:read scope can call GET /ccm/api/1.0/groups and receive every group on the site regardless of the view permissions on those groups, disclosing the organization's group structure, roles, and access hierarchy. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 6.0 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.
Published: 2026-09-11
Score: 6 Medium
EPSS: n/a
KEV: No
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Remediation

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History

Fri, 11 Sep 2026 23:45:00 +0000

Type Values Removed Values Added
Description Concrete CMS 9.2.0 to 9.5.2 contain a missing authorization vulnerability in the REST API Groups list endpoint. The listGroups() method in concrete/src/Api/Controller/Groups.php registers a permissions checker callback that unconditionally returns true, so no per-object (tree node) authorization is enforced when the group collection is returned. An authenticated user whose API token carries the groups:read scope can call GET /ccm/api/1.0/groups and receive every group on the site regardless of the view permissions on those groups, disclosing the organization's group structure, roles, and access hierarchy. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 6.0 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.
Title Missing Authorization in Concrete CMS 9.2.0 to 9.5.2 REST API Groups List Endpoint Allows Authenticated Users to Enumerate All Groups
Weaknesses CWE-862
References
Metrics cvssV4_0

{'score': 6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: ConcreteCMS

Published:

Updated: 2026-09-11T19:22:43.122Z

Reserved: 2026-08-27T18:21:25.200Z

Link: CVE-2026-81908

cve-icon Vulnrichment

Updated: 2026-09-11T19:22:27.431Z

cve-icon NVD

Status : Deferred

Published: 2026-09-11T18:16:58.810

Modified: 2026-09-11T20:19:13.417

Link: CVE-2026-81908

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses