CVE-2026-97846

Keycloak-services: keycloak-services: standard token exchange v2 bypasses mtls holder-of-key binding

Published Sep 25, 2026 CVSS 3.1 · 6.8 Medium EPSS < 1% KEV · Not listed
Description
Keycloak provides a feature called mTLS holder-of-key binding which ensures that a token can only be used by the client that originally requested it by binding it to their digital certificate. A flaw was discovered where the new Standard Token Exchange V2 feature does not check for this certificate. This allows an attacker with stolen client credentials to obtain a standard, unrestricted token that bypasses these security protections.

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
CPEs cpe:/a:redhat:build_keycloak: cpe:/a:redhat:build_keycloak:26.6::el9
References
Type Values Removed Values Added
First Time appeared Redhat build Of Keycloak
Redhat single Sign-on
Vendors & Products Redhat build Of Keycloak
Redhat single Sign-on
Type Values Removed Values Added
Metrics ssvc

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

Type Values Removed Values Added
Description Keycloak provides a feature called mTLS holder-of-key binding which ensures that a token can only be used by the client that originally requested it by binding it to their digital certificate. A flaw was discovered where the new Standard Token Exchange V2 feature does not check for this certificate. This allows an attacker with stolen client credentials to obtain a standard, unrestricted token that bypasses these security protections.
Title Keycloak-services: keycloak-services: standard token exchange v2 bypasses mtls holder-of-key binding
First Time appeared Redhat
Redhat build Keycloak
Redhat red Hat Single Sign On
Weaknesses CWE-287
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
Metrics cvssV3_1

{'score': 6.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Nov 6, 2026, 10:27 AM
Reserved
Sep 25, 2026, 5:55 AM
Status
Awaiting Analysis
Published
Sep 25, 2026, 7:16 AM
Modified
Nov 6, 2026, 11:17 AM
Severity
Moderate
Public date
Sep 24, 2026, 4:58 PM