CVE-2026-4874: Org.keycloak.protocol.oidc.grants: org.keycloak.services.managers: keycloak: server-side request forgery via oidc token endpoint manipulation

Severity: low (CVSS 3.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-26 · updated 2026-06-26
Weakness: CWE-918

Description

A flaw was found in Keycloak. An authenticated attacker can perform Server-Side Request Forgery (SSRF) by manipulating the `client_session_host` parameter during refresh token requests. This occurs when a Keycloak client is configured to use the `backchannel.logout.url` with the `application.session.host` placeholder. Successful exploitation allows the attacker to make HTTP requests from the Keycloak server’s network context, potentially probing internal networks or internal APIs, leading to information disclosure.

Affected products

Red Hat build of Keycloak 26.4: all versions
Red Hat JBoss EAP: 8.0.0
RedHat Jboss Enterprise Application Platform Expansion Pack: all versions
Red Hat Single Sign-On: 7.0

References

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