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…
Published: 2026-05-20 · CVSS: 6.4 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7