CVE-2026-81906 — [UNREVIEWED] OAuth Callback Login Bypasses Deactivated-Account Checks

Description (CNA)

Concrete CMS OAuth callback login path prior to version 9.5.3 did not check whether an account was active or email-validated before establishing a session. A deactivated or unvalidated user with an existing OAuth binding could complete authentication and receive a session that was fully authenticated for the callback response, with the login recorded and login events dispatched. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 6.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.

Affected (CNA)

Vendor / product	Versions
Concrete CMS / Concrete CMS	affected 5.0.0 through 9.5.2

CWE

CWE-288

References

https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.