medium6.4
CVE-2026-9087
Keycloak: Insufficient verification proof scoping enables identity provider account linking attack and account compromise
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| maven | org.keycloak:keycloak-services | < 26.6.3 | 26.6.3 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Redhat | Build Of Keycloak | All versions |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-m6qj-3mpp-57v8
- https://nvd.nist.gov/vuln/detail/CVE-2026-9087
- https://access.redhat.com/security/cve/CVE-2026-9087
- https://bugzilla.redhat.com/show_bug.cgi?id=2480172
- https://access.redhat.com/errata/RHSA-2026:25098
- https://github.com/keycloak/keycloak/commit/37dabf59d0b5ca3e5b3b272bcd3b2580e67b94dd
- https://access.redhat.com/errata/RHSA-2026:25097
- https://github.com/keycloak/keycloak/releases/tag/26.6.3
- https://access.redhat.com/errata/RHSA-2026:30049
- https://access.redhat.com/errata/RHSA-2026:30050