medium6.5
CVE-2026-9796
Keycloak has a Time-of-check Time-of-use (TOCTOU) Race Condition
Impact
A flaw was found in Keycloak. An authenticated administrator with the `manage-clients` role can exploit a Time-of-check to time-of-use (TOCTOU) vulnerability in the name-based admin role checks. This allows the attacker to escalate their privileges to `realm-admin` for all users within the realm, granting them extensive control over the system. The composite role relationship persists even after the attacker's own permissions are revoked and across system reboots.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| maven | org.keycloak:keycloak-server | < 26.6.4 | 26.6.4 |
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-pq65-77rc-7r8c
- https://nvd.nist.gov/vuln/detail/CVE-2026-9796
- https://access.redhat.com/security/cve/CVE-2026-9796
- https://bugzilla.redhat.com/show_bug.cgi?id=2482464
- https://github.com/keycloak/keycloak/issues/49427
- https://github.com/keycloak/keycloak/pull/49624
- https://github.com/keycloak/keycloak/commit/39cb8de54c8517efeda4baa8bc314fd40e9c6934
- https://access.redhat.com/errata/RHSA-2026:56523
- https://access.redhat.com/errata/RHSA-2026:56524