CVE-2026-9087 Keycloak: cross-session email verification proof not bound to upstream identity in first-broker-login

A flaw was found in Keycloak. The cross-session verification proof is keyed only by local userId, idpAlias and is not bound to the upstream identity that was actually verified, so a second upstream account on the same IdP can consume it and get linked to the victim's local account...

CVE-2026-9087 Keycloak: cross-session email verification proof not bound to upstream identity in first-broker-login

A flaw was found in Keycloak. The cross-session verification proof is keyed only by local userId, idpAlias and is not bound to the upstream identity that was actually verified, so a second upstream account on the same IdP can consume it and get linked to the victim's local account...

CVE-2026-9087

CVE-2026-9087 : In Keycloak, the cross-session verification proof is keyed only by (local userId, idpAlias) and is not bound to the upstream identity actually verified, allowing a second upstream account on the same IdP to be linked to the victim’s local account. Affected component: Keycloak auth...