Keycloak Server-Side Request Forgery via OIDC token endpoint manipulation
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.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-4874US | low3.1 | — | ||
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 requ… | ||||
references
External citations — patches, advisories, analysis.
- https://access.redhat.com/errata/RHSA-2026:25097WEB
- https://access.redhat.com/errata/RHSA-2026:25098WEB
- https://access.redhat.com/errata/RHSA-2026:30049WEB
- https://access.redhat.com/errata/RHSA-2026:30050WEB
- https://access.redhat.com/security/cve/CVE-2026-4874WEB
- https://bugzilla.redhat.com/show_bug.cgi?id=2451611WEB
- https://github.com/keycloak/keycloakPACKAGE
- https://github.com/keycloak/keycloak/commit/00dd0dd716c4319d3bac3eb2f2ac22d2a94f79fdWEB
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