EUVD-2026-80892
GHSA-pmgv-hgv2-w69h
Severity by source
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:A/VC:L/VI:L/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
Attacker must have held a valid pre-existing token and race token expiry (AC:H), was an authenticated user (PR:L); stale API access yields limited C:L/I:L and no availability impact.
Primary rating from Vendor (ConcreteCMS).
CVSS VectorVendor: ConcreteCMS
Lifecycle Timeline
1DescriptionCVE.org
Concrete CMS before 9.5.4 re-authorized OAuth REST API requests from the bearer token alone and did not re-check the state of the account the token had been issued to. The resource server's authorization validator confirmed only that a token existed, had not expired, and had not been explicitly revoked, and deactivating a user did not revoke that user's outstanding tokens. As a result, a deactivated user retained full access to /ccm/api/1.0/* for the remaining lifetime of any token already issued to them. The same gap applied to accounts that had been deleted or locked pending a forced password reset. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.0 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Myq Larson for reporting.
AnalysisAI
Deactivated, deleted, or password-reset-locked Concrete CMS accounts keep working API access via any bearer token issued to them before the account state change, letting the holder continue calling the OAuth REST API endpoints under /ccm/api/1.0/* until that already-issued token expires on its own. All Concrete CMS versions before 9.5.4 are affected when the OAuth REST API is enabled; the vendor rates this only 2.0 (CVSS v4.0) and our independent assessment aligns with a low-impact, high-complexity authenticated issue, with no public exploit identified at time of analysis. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Requires that (1) the Concrete CMS OAuth REST API is enabled and in use, (2) the attacker previously held a valid, unexpired, non-revoked bearer token issued to their own account, and (3) that account was subsequently deactivated, deleted, or locked for a forced password reset WITHOUT the outstanding token being revoked. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | This is genuinely low-priority, and the signals are consistent rather than conflicting. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Vendor-released patch: upgrade to Concrete CMS 9.5.4, which is the first release containing the corrected authorization validator (release notes: https://documentation.concretecms.org/developers/introduction/version-history/954-release-notes). … Detailed patch versions, workarounds, and compensating controls in full report. |
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External POC / Exploit Code
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