PatchTheCVECVE-2026-6826: Concrete CMS 9.5.0 and below is vulnerable to unauthenticated file usage disclosure via missing permission ch
CVE-2026-6826 is a medium-severity flaw (CVSS 5.3) affecting concrete cms. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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 vulner
Why this priority
- Public exploit reference
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 5.3 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 1.5% (top 27%) |
| CISA exploited list | No |
| Weakness | CWE-200 |
| Published | 2026-05-21 |
| Last modified | 2026-07-23 |
Last updated 2026-07-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- Metasploit: Concrete CMS Unauthenticated File Usage Disclosure
- Nuclei scan template: Concrete CMS <9.5.1 - Unauthenticated File Usage Disclosure
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-6826?
concrete cms: upgrade to 9.5.1. Exact commands for each OS are on this page.
Is CVE-2026-6826 being exploited?
CVE-2026-6826 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-6826 affect?
CVE-2026-6826 affects concrete cms. Severity is medium (CVSS 5.3). 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 re
How urgent is CVE-2026-6826?
Priority 47/100. Public exploit reference; Remotely exploitable, no login, no user action
Related CVEs
- CVE-2026-18111 MEDIUM 6.1 UPGRADE Concrete CMS 9 before 9.5.3 was vulnerable to stored cross-site scripting (XSS) in the Feature, Feature Link,
- CVE-2026-18117 MEDIUM 5.4 UPGRADE Concrete CMS 9.0.0 through 9.5.3 is vulnerable to stored XSS via the custom page alias name (customAliasName)
- CVE-2026-68526 MEDIUM 4.3 UPGRADE Concrete CMS before 9.5.3 did not validate an anti-CSRF token in the Calendar event duplicate dialog controlle
- CVE-2026-81912 MEDIUM 5.7 UPGRADE Concrete CMS before 9.5.3 is vulnerable to Cross-Site Request Forgery in the Move Multiple Groups feature
- CVE-2026-81913 MEDIUM 6.1 UPGRADE Concrete CMS versions 9.5.0 through 9.5.2 are vulnerable to Open Redirect via the rcURL parameter