CVE-2026-8236: Concrete CMS is vulnerable to IDOR combined with a missing authentication gate

May 22, 2026 (updated June 24, 2026)

Concrete CMS 9.5.0 and below is vulnerable to IDOR combined with a missing authentication gate. The endpoint /ccm/system/dialogs/file/usage/{fID} accepts an integer file ID in the URL and returns internal site structure data (page IDs, versions, URL paths) to anyone who sends a GET request.

References

documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes
github.com/advisories/GHSA-58c8-vvqw-cm7m
nvd.nist.gov/vuln/detail/CVE-2026-8236

Code Behaviors & Features

Detect and mitigate CVE-2026-8236 with GitLab Dependency Scanning

Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Learn more about Dependency Scanning →