Description
A flaw was found in Keycloak. When the JSON Web Token (JWT) authorization grant preview feature is enabled and a user account is disabled, Keycloak fails to validate the user’s disabled status during JWT authorization grant processing. A remote attacker with low privileges can exploit this improper access control vulnerability by presenting a valid assertion token from an external identity provider to obtain a JWT for a disabled user. This allows unauthorized access to sensitive resources.
Affected products
redhat: build of keycloak
References7
- access.redhat.com/security/cve/CVE-2026-1609 Vendor Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2435257 Issue TrackingVendor Advisory
- access.redhat.com/security/cve/CVE-2026-1609 Vendor Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2435257 Issue TrackingVendor Advisory
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-1609.… Vendor Advisory
- github.com/keycloak/keycloak/issues/46144 Issue Tracking
- github.com/keycloak/keycloak/releases/tag/26.5.3 Release Notes
Metrics
- CVSS 3.1
-
8.1
HIGH
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - EPSS — exploit probability
- 1% percentile: 47 · as of 15 November 2026
- CWE
- CWE-284
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.