CVE-2026-6826
Concrete 9.5.0 and below has file usage disclosure via missing permission check in Usage controller
Concrete CMS 9.5.0 and below is vulnerable to unauthenticated file usage disclosure via missing permission check in the usage controller. Any unauthenticated visitor can request /ccm/system/dialogs/file/usage/{fID} with any file ID and receive a list of every page that references that file, including page IDs, handles, and full URLs. This includes pages that are otherwise restricted by permissions.The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 6.9 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Eldudareeno for reporting.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Concrete 9.5.0 and below has file usage disclosure via missing permission check in Usage controller
Concrete CMS 9.5.0 and below is vulnerable to unauthenticated file usage disclosure via missing permission check in the usage controller. Any unauthenticated visitor can request /ccm/system/dialogs/file/usage/{fID} with any file ID and receive a list of every page that references that file, including page IDs, handles, and full URLs. This includes pages that are otherwise restricted by permissions.The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 6.9 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Eldudareeno for reporting.
- Record
CVE-2026-6826- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-200
- Updated
- 2026-11-02
EUVDEUVD-2026-31344
Concrete CMS 9.5.0 and below is vulnerable to unauthenticated file usage disclosure via missing permission check in the usage controller. Any unauthenticated visitor can request /ccm/system/dialogs/file/usage/{fID} with any file ID and receive a list of every page that references that file, including page IDs, handles, and full URLs. This includes pages that are otherwise restricted by permissions.The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 6.9 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Eldudareeno for reporting.
- Record
EUVD-2026-31344- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-4g7q-44qp-cc5c
Concrete CMS is vulnerable to unauthenticated file usage disclosure
Concrete CMS 9.5.0 and below is vulnerable to unauthenticated file usage disclosure via missing permission check in the usage controller. Any unauthenticated visitor can request /ccm/system/dialogs/file/usage/{fID} with any file ID and receive a list of every page that references that file, including page IDs, handles, and full URLs. This includes pages that are otherwise restricted by permissions. Concrete CMS thanks Eldudareeno for reporting this issue.
- Record
GHSA-4g7q-44qp-cc5c- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-200
- Updated
- 2026-11-02
NVD
Concrete CMS 9.5.0 and below is vulnerable to unauthenticated file usage disclosure via missing permission check in the usage controller. Any unauthenticated visitor can request /ccm/system/dialogs/file/usage/{fID} with any file ID and receive a list of every page that references that file, including page IDs, handles, and full URLs. This includes pages that are otherwise restricted by permissions.The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 6.9 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Eldudareeno for reporting.
- Record
CVE-2026-6826- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-200
- Updated
- 2026-11-02
OSV
Concrete 9.5.0 and below has file usage disclosure via missing permission check in Usage controller
Concrete CMS 9.5.0 and below is vulnerable to unauthenticated file usage disclosure via missing permission check in the usage controller. Any unauthenticated visitor can request /ccm/system/dialogs/file/usage/{fID} with any file ID and receive a list of every page that references that file, including page IDs, handles, and full URLs. This includes pages that are otherwise restricted by permissions.The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 6.9 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Eldudareeno for reporting.
- Record
CVE-2026-6826- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-200
- Updated
- 2026-11-02
OSVGHSA-4g7q-44qp-cc5c
Concrete CMS is vulnerable to unauthenticated file usage disclosure
Concrete CMS 9.5.0 and below is vulnerable to unauthenticated file usage disclosure via missing permission check in the usage controller. Any unauthenticated visitor can request /ccm/system/dialogs/file/usage/{fID} with any file ID and receive a list of every page that references that file, including page IDs, handles, and full URLs. This includes pages that are otherwise restricted by permissions. Concrete CMS thanks Eldudareeno for reporting this issue.
- Record
GHSA-4g7q-44qp-cc5c- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-200
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
concrete5/concrete5Packagist |
before 9.5.1 | 9.5.1 |
concrete5/concrete5Packagist |
before 9.5.1, plus listed versions 8.08.0.18.0.28.0.38.1.0 Show 45 moreShow less8.2.08.2.0RC28.2.18.3.08.3.18.3.28.4.08.4.0RC38.4.0RC48.4.18.4.28.4.38.4.48.4.58.5.08.5.0RC18.5.0RC28.5.18.5.108.5.118.5.128.5.138.5.148.5.158.5.168.5.178.5.188.5.198.5.28.5.208.5.218.5.38.5.48.5.58.5.68.5.6RC18.5.78.5.88.5.99.0.09.0.0RC19.0.0RC39.0.0RC49.0.19.0.2 |
9.5.1 |
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| Metasploit | Concrete CMS Unauthenticated File Usage Disclosure | 2026-05-21 |
| Nuclei | Concrete CMS <9.5.1 - Unauthenticated File Usage Disclosure |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, Metasploit, Nuclei, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-6826 is a medium vulnerability (CVSS 6.9) in Concrete Cms Cms, published May 21, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.46%, the 73rd percentile. Fixed in concrete5/concrete5 9.5.1.
References
Left out here: 39 versions. The JSON record has them.