CVE-2026-18569 Keycloak-services: keycloak-services: oidc backchannel logout accepts unsigned forged logout tokens
Attackers can force user logouts by sending unsigned tokens when signature validation is disabled, disrupting active sessions.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-18569?
CVE-2026-18569 is a low-severity vulnerability in Redhat Build of Keycloak, published on 4 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-347
Which versions are affected by CVE-2026-18569?
It affects 1 product.
Products include Redhat Build of Keycloak.
How do I fix CVE-2026-18569?
No fix has been published for CVE-2026-18569 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-18569 being exploited?
There is no known exploitation of CVE-2026-18569 in the wild and no public exploit code.
Other vulnerabilities in Redhat Build of Keycloak
- CVE-2026-15572 Keycloak-services: keycloak-services: dcr protocol mapper type-swap policy bypass allows privilege escalation
- CVE-2026-3047 Keycloak SAML Broken has Authentication Bypass by Primary Weakness
- CVE-2026-15573 Keycloak-services: keycloak-services: authorization bypass via unnormalized uri matching in pathmatcher
- CVE-2026-16102 Keycloak-services: keycloak-services: default dcr policy allows role forgery via user property mappers
- CVE-2026-1609 Org.keycloak/keycloak-quarkus-server: keycloak: unauthorized access via jwt authorization grant with disabled users
Sources
Also known as GHSA-pcf4-9g97-7cpf.