EUVD-2026-78830
GHSA-7hmf-f7jv-m4xw
Severity by source
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Primary rating from Vendor (ConcreteCMS) · only source for this CVE.
CVSS VectorVendor: ConcreteCMS
Lifecycle Timeline
2DescriptionCVE.org
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.
AnalysisAI
Unauthenticated user enumeration in Concrete CMS 9.0.0 through 9.5.2 allows any anonymous visitor to dump the complete backend account list — including internal user IDs, usernames and email addresses of every administrator and the super-administrator (user ID 1) — by sending an empty search to the /ccm/system/user/autocomplete endpoint and paginating the results. The endpoint enforces only a CSRF-style token that is bound to the selector's display options rather than to caller identity, and that token is handed out to anonymous visitors, so there is no authentication or privilege barrier to clear. …
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External POC / Exploit Code
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