CVE-2026-4874: Keycloak Server-Side Request Forgery via OIDC token endpoint manipulation

March 26, 2026 (updated April 13, 2026)

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.

References

access.redhat.com/security/cve/CVE-2026-4874
bugzilla.redhat.com/show_bug.cgi?id=2451611
github.com/advisories/GHSA-22rm-wp4x-v5cx
github.com/keycloak/keycloak
nvd.nist.gov/vuln/detail/CVE-2026-4874

Code Behaviors & Features

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