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TI-2026-56519 Aliases CVE-2026-81908GHSA-865j-87f7-7r6w

Missing authorization in Concrete CMS

Priority LOW 27CWE-862Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
Security bypass
Confidentiality · integrity · availability
High · None · None
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-862.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00393 33rd percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

No affected products listed by the sources yet.

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:*——Concrete CMS
  • cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:* Versions — — ·Concrete CMS

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-81908
  2. 2026-10-03 Alias added: GHSA-865j-87f7-7r6w

References

Other 1

  • TI-2026-23602 ConcreteCMS v9.4.7 contains a Denial of Service (DoS) vulnerability in the File Manager… CVSS 3.1MEDIUM 6.5
  • TI-2023-23992 A Cross Site Scripting (XSS) vulnerability in Concrete CMS from versions 9.2.0 to 9.2.2… CVSS 3.1MEDIUM 5.4
  • TI-2023-26495 Concrete CMS before 8.5.13 and 9.x before 9.2.2 allows unauthorized access because… CVSS 3.1CRITICAL 9.8
  • TI-2026-14907 Missing authorization in Concrete CMS CVSS 4.0HIGH 8.7
  • TI-2022-06200 Cleartext transmission of sensitive information in https://github.com/concrete5/concrete5 CVSS 3.1CRITICAL 9.8
  • TI-2021-17294 An issue was discovered in Concrete CMS through 8.5.5. CVSS 3.1CRITICAL 9.8
See all 220 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences