CVE-2026-9087: Keycloak: Insufficient verification proof scoping enables identity provider account linking attack and account compromise
(updated )
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.
References
- access.redhat.com/errata/RHSA-2026:25097
- access.redhat.com/errata/RHSA-2026:25098
- access.redhat.com/errata/RHSA-2026:30049
- access.redhat.com/errata/RHSA-2026:30050
- access.redhat.com/security/cve/CVE-2026-9087
- bugzilla.redhat.com/show_bug.cgi?id=2480172
- github.com/advisories/GHSA-m6qj-3mpp-57v8
- github.com/keycloak/keycloak/commit/37dabf59d0b5ca3e5b3b272bcd3b2580e67b94dd
- github.com/keycloak/keycloak/releases/tag/26.6.3
- nvd.nist.gov/vuln/detail/CVE-2026-9087
Code Behaviors & Features
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