CVE-2026-8236Network attack vector

Unauthenticated site structure disclosure via file ID

Published May 21, 2026 · Updated May 21, 2026

Missing authorization in Concrete CMS 9.5.0 and earlier allows remote attackers to read internal site structure data via a GET request. The /ccm/system/dialogs/file/usage/{fID} endpoint accepts an attacker-selected integer file ID and returns page IDs, versions, and URL paths without authenticating the requester. No account or user interaction is required, but exploitation depends on supplying a valid file ID and discloses structure metadata rather than file contents.

CVSS severity6.3
Medium
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Concrete CMS 9.5.0 and earlier allows remote attackers to read internal site structure data via a GET request. The /ccm/system/dialogs/file/usage/{fID} endpoint accepts an attacker-selected integer file ID and returns page IDs, versions, and URL paths without authenticating the requester. No account or user interaction is required, but exploitation depends on supplying a valid file ID and discloses structure metadata rather than file contents.

The record

CVE
CVE-2026-8236
Published
May 21, 2026
Updated
May 21, 2026
Vendor
Concrete CMS
Product
Concrete CMS
Classifications
CWE-862
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 21, 2026CVE publishedPublication date reported by the CVE source.
  2. May 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5 <=9.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Concrete CMS · Concrete CMSversion=5 <=9.5.0

Published CVSS scores

4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
6.3ConcreteCMSCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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