Description
A flaw was found in the backchannel logout endpoint of the keycloak-services component, which is part of the Red Hat Build of Keycloak. This component handles authentication and session management for applications. The issue occurs when an OIDC identity provider is configured to skip signature validation. In this specific setup, the system incorrectly accepts logout requests that have no cryptographic signature. An attacker who knows certain technical details about a user's session can use this flaw to force that user to be logged out, potentially disrupting their work.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat build of Keycloak 26.6 | — | — |
| Red Hat | Red Hat build of Keycloak 26.6.8 | — | — |
| Red Hat | Red Hat Data Grid 8 | — | — |
| Red Hat | Red Hat JBoss Enterprise Application Platform Expansion Pack | — | — |
| Red Hat | Red Hat Single Sign-On 7 | — | — |
Advisories 1
- WID-SEC-2026-2634 RedHat Build of Keycloak: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Nov 8, 2026
References
- RHSA-2026:95761 vendor-advisory
- RHSA-2026:95762 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-18569 vdb-entry
- RHBZ#2509755 issue-tracking