CVE-2026-18110

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Source

https://cve.org/CVERecord?id=CVE-2026-18110

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-18110.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-18110

Published

2026-09-15T16:33:36Z

Modified

2026-09-17T03:45:37Z

Severity

8.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N CVSS Calculator

Summary

Concrete CMS 9.0.0 through 9.5.2 is vulnerable to missing authorization in the user selector autocomplete endpoint (/ccm/system/user/autocomplete), allowing an unauthenticated attacker to retrieve the complete backend user directory — internal ID, username

Details

Concrete CMS 9 (9.0.0 through 9.5.2) does not perform an authorization check on the user selector autocomplete endpoint (/ccm/system/user/autocomplete), which backs the "Preview as User" panel and other user-selector components. The endpoint validates only a CSRF-style access token that is bound to the selector's display options rather than to the caller's identity or permissions, and that token is issued to anonymous visitors because the selector renders without an authorization check. Because an empty query resolves to a match-all filter, an unauthenticated attacker can submit an empty search and paginate the results to enumerate every backend account, disclosing the internal user ID, username, and email address of all administrative users, including the super-administrator (user ID 1). No password hashes or session material are disclosed The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 8.7 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks thirtythree and YesWeHack for reporting.

Database specific

{
    "cna_assigner": "ConcreteCMS",
    "cwe_ids": [
        "CWE-862"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18110.json"
}

References

Affected packages

Git / github.com/concretecms/concretecms

Affected ranges

Type

GIT

Repo

https://github.com/concretecms/concretecms

Events

Introduced

b3774abddd475b4ba98b637402506f7a5ebd90ea

Last Affected

8fe9708072c3815a5df719b592e4b23b43b4ff7a

Database specific

Show details

{
    "extracted_events": [
        {
            "introduced": "9.0.0"
        },
        {
            "last_affected": "9.5.2"
        }
    ],
    "source": "AFFECTED_FIELD"
}

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-18110.json"