Vulnerability · CVE-2026-6826
Concrete CMS 9.5.0 and below is vulnerable to unauthenticated file usage disclosure via missing permission check in the usage controller.
Published May 21, 2026 · catalog updated Jul 23, 2026 · concrete cms
Check if you run it
No confirmed exploitation is on record for CVE-2026-6826. EPSS is 1.28%. Act only if a listed version of concrete cms is installed.
Gaps on this record
- No version range is stored. A customer cannot check an installed version against this record.
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
- Severity
- Medium6.9
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 1.28%
- Remediation
- Not established
- Affected products
- cpe concretecms/concrete cms
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.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- cpe concretecms/concrete cmsversion unspecified
How to fix CVE-2026-6826
Recommended remediation
No required-action text, fix commit, or clear fixed-version range is stored yet.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-6826. EPSS is 1.28%. Act only if a listed version of concrete cms is installed.
Which versions are affected?
Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
CWE-200: Exposure of Sensitive Information. EPSS 1.28%. There is no CISA KEV listing. A public exploit reference is linked in Sources. That is not the same as confirmed exploitation. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
May 21, 2026 · NIST NVD
Detected
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
Jul 23, 2026 · NIST NVD
Updated
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
Sources
- CVE.orgVulnerability recordCVE-2026-6826
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-6826
30-day exploitation probability 1.3%
first.org - Metasploit ModulesPublic exploit moduleauxiliary_scanner/http/concrete_cms_file_usage_disclosure
Public module reference (normal). Module source is not copied into this catalog.
rapid7.com - NIST NVDVulnerability recordCVE-2026-6826
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 referenc
nvd.nist.gov
References
Freshness
Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.