CVE-2026-8236CWE-862

Concrete CMS 9.5.0 and below is vulnerable to IDOR combined with a missing authentication gate for endpoint /ccm/system/dialogs/file/usage/{fID}

Medium · published May 21, 2026

CVSS v4.0
6.3
EPSS
1%
Percentile
58.7
In the wild
Unconfirmed
What it is

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. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 6.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.

The record
Technical detail
CVSS v4.0
6.3 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
EPSS
0.00879 · 58.7th percentile
Weakness
CWE-862 · Missing Authorization
Published
2026-05-21T20:59Z
EPSS history
Timeline
  • 21 MAY 20:59Z
    Concrete CMS 9.5.0 and below is vulnerable to IDOR combined with a missing authentication gate for endpoint /ccm/system/dialogs/file/usage/{fID}
    cvelistv5