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Vulnerability · Published Aug 4, 2026 · Assigned by redhat

CVE-2026-18569Keycloak-services: keycloak-services: oidc backchannel logout accepts unsigned forged logout tokens

Low 3.7

In plain English

A low-severity security flaw in Red Hat build of Keycloak 26.6 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities).

Severity (CVSS 3.1)3.7Low
Exploit odds (30 days)0.2%top 83.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

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.

Affected products (as reported)

VendorProductVersions
Red Hat Red Hat build of Keycloak 26.6 see references
Red Hat Red Hat build of Keycloak 26.6 see references
Red Hat Red Hat build of Keycloak 26.6 see references
Red Hat Red Hat build of Keycloak 26.6.8 see references
Red Hat Red Hat build of Keycloak 26.6.8 see references
Red Hat Red Hat build of Keycloak 26.6.8 see references
Red Hat Red Hat Data Grid 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack see references
Red Hat Red Hat Single Sign-On 7 see references

Weakness: CWE-347 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

References