CVE-2026-96447

Keycloak-services: keycloak-services: stateless token preferred_username fallback enables identity rebinding

Published Nov 6, 2026 CVSS 3.1 · 4.2 Medium EPSS < 1% KEV · Not listed
Description
A flaw was found in the TokenManager component of Keycloak, an open-source identity and access management solution. The issue occurs during the validation of stateless access tokens when the original user ID no longer exists. Keycloak incorrectly falls back to using the username to identify the user without verifying if the identity matches the original token subject. This could allow an attacker with an old token to gain access to a newly created service account if it shares the same client ID as a previously deleted one.

Remediation

Vendor Workaround

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
CPEs cpe:/a:redhat:build_keycloak: cpe:/a:redhat:build_keycloak:26.6::el9
References
Type Values Removed Values Added
Title keycloak-services: keycloak-services: Stateless token preferred_username fallback enables identity rebinding Keycloak-services: keycloak-services: stateless token preferred_username fallback enables identity rebinding
First Time appeared Redhat
Redhat build Keycloak
Redhat red Hat Single Sign On
CPEs cpe:/a:redhat:build_keycloak:
cpe:/a:redhat:red_hat_single_sign_on:7
Vendors & Products Redhat
Redhat build Keycloak
Redhat red Hat Single Sign On
References
Type Values Removed Values Added
Description A flaw was found in the TokenManager component of Keycloak, an open-source identity and access management solution. The issue occurs during the validation of stateless access tokens when the original user ID no longer exists. Keycloak incorrectly falls back to using the username to identify the user without verifying if the identity matches the original token subject. This could allow an attacker with an old token to gain access to a newly created service account if it shares the same client ID as a previously deleted one.
Title keycloak-services: keycloak-services: Stateless token preferred_username fallback enables identity rebinding
Weaknesses CWE-287
References
Metrics threat_severity

None

cvssV3_1

{'score': 4.2, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N'}

threat_severity

Moderate

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Nov 6, 2026, 5:36 PM
Reserved
Sep 23, 2026, 9:37 AM
Status
Awaiting Analysis
Published
Nov 6, 2026, 6:16 AM
Modified
Nov 6, 2026, 6:18 PM
Severity
Moderate
Public date
Nov 5, 2026, 12:00 AM