Description
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.
Problem types
Authorization Bypass Through User-Controlled Key
Product status
Timeline
| 2026-05-20: | Reported to Red Hat. |
| 2026-05-20: | Made public. |
References
access.redhat.com/security/cve/CVE-2026-9087
bugzilla.redhat.com/show_bug.cgi?id=2480172 (RHBZ#2480172)