CVE-2026-109082

Keycloak-services: keycloak-services: ciba confidential-only contract not enforced for public clients

Published Oct 12, 2026 CVSS 3.1 · 6.8 Medium EPSS < 1% KEV · Not listed
Description
A flaw was found in the Client-Initiated Backchannel Authentication CIBA implementation within the keycloak-services component of Keycloak. This component handles advanced authentication flows where a client initiates a login on behalf of a user. The issue occurs because Keycloak fails to verify that a client is authorized to use the CIBA flow, allowing public clients to bypass security requirements. An attacker could use this flaw to trick a user into approving a login request, eventually gaining full access to the users account without needing a client secret.

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': 'total'}, 'version': '2.0.3'}

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
First Time appeared Redhat red Hat Single Sign On
CPEs cpe:/a:redhat:red_hat_single_sign_on:7
Vendors & Products Redhat red Hat Single Sign On
Type Values Removed Values Added
Description A flaw was found in the Client-Initiated Backchannel Authentication CIBA implementation within the keycloak-services component of Keycloak. This component handles advanced authentication flows where a client initiates a login on behalf of a user. The issue occurs because Keycloak fails to verify that a client is authorized to use the CIBA flow, allowing public clients to bypass security requirements. An attacker could use this flaw to trick a user into approving a login request, eventually gaining full access to the users account without needing a client secret.
Title Keycloak-services: keycloak-services: ciba confidential-only contract not enforced for public clients
First Time appeared Redhat
Redhat build Keycloak
Weaknesses CWE-287
CPEs cpe:/a:redhat:build_keycloak:
Vendors & Products Redhat
Redhat build Keycloak
References
Metrics cvssV3_1

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

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Oct 15, 2026, 3:16 PM
Reserved
Oct 12, 2026, 6:09 AM
Status
Awaiting Analysis
Published
Oct 12, 2026, 7:16 AM
Modified
Oct 15, 2026, 4:33 PM
Severity
Moderate
Public date
Oct 9, 2026, 6:42 PM