Concrete CMS 8.5.3 through 9.5.2 enabled the OAuth 2.0 refresh-token grant using the unmodified upstream League grant, which issued new access tokens from a valid refresh token without re-checking the associated account's active status. A user who obtained a refresh token while active could therefore continue to mint valid access tokens after being deactivated or suspended (uIsActive=0), so deactivating an account did not revoke its API access. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L. Thanks sh4d0byss for reporting.
Metrics
Affected Vendors & Products
References
History
Fri, 18 Sep 2026 15:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:* | |
| Metrics |
cvssV3_1
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Tue, 15 Sep 2026 22:15:00 +0000
| Type | Values Removed | Values Added |
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| First Time appeared |
Concretecms
Concretecms concrete Cms |
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| Vendors & Products |
Concretecms
Concretecms concrete Cms |
Tue, 15 Sep 2026 20:30:00 +0000
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| Metrics |
ssvc
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Tue, 15 Sep 2026 19:00:00 +0000
| Type | Values Removed | Values Added |
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| Description | Concrete CMS 8.5.3 through 9.5.2 enabled the OAuth 2.0 refresh-token grant using the unmodified upstream League grant, which issued new access tokens from a valid refresh token without re-checking the associated account's active status. A user who obtained a refresh token while active could therefore continue to mint valid access tokens after being deactivated or suspended (uIsActive=0), so deactivating an account did not revoke its API access. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L. Thanks sh4d0byss for reporting. | |
| Title | In Concrete CMS 8.5.3 to 9,5,2, OAuth 2.0 Refresh-Token Grant Bypasses Account Status | |
| Weaknesses | CWE-862 | |
| References |
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| Metrics |
cvssV4_0
|
Status: PUBLISHED
Assigner: ConcreteCMS
Published: 2026-09-15T18:48:52.840Z
Updated: 2026-09-15T19:28:31.335Z
Reserved: 2026-08-27T18:23:01.366Z
Link: CVE-2026-81921
Updated: 2026-09-15T19:28:27.763Z
Status : Analyzed
Published: 2026-09-15T19:17:41.483
Modified: 2026-09-18T15:29:38.830
Link: CVE-2026-81921
No data.