CVE-2026-81921

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Source

https://cve.org/CVERecord?id=CVE-2026-81921

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-81921.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-81921

Published

2026-09-15T18:48:52Z

Modified

2026-09-16T11:30:19Z

Severity

2.3 (Low) CVSS_V4 - 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 CVSS Calculator

Summary

In Concrete CMS 8.5.3 to 9,5,2, OAuth 2.0 Refresh-Token Grant Bypasses Account Status

Details

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.

Database specific

{
    "cna_assigner": "ConcreteCMS",
    "cwe_ids": [
        "CWE-862"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81921.json"
}

References

Affected packages

Git / github.com/concretecms/concretecms

Affected ranges

Type

GIT

Repo

https://github.com/concretecms/concretecms

Events

Introduced

372795cb4e97d9ca336c4b5623773e3b320c122a

Last Affected

8fe9708072c3815a5df719b592e4b23b43b4ff7a

Database specific

Show details

{
    "extracted_events": [
        {
            "introduced": "8.5.3"
        },
        {
            "last_affected": "9.5.2"
        }
    ],
    "source": "AFFECTED_FIELD"
}

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-81921.json"