8.1
High
CVE-2026-11800 A flaw was found in Keycloak
Description
A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to impersonate any federated user linked to the affected Identity Provider, leading to unauthorized access and potential privilege escalation.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Red Hat build of Keycloak 26.6 26.6 | earliest → < 26.6-8 | 26.6-8 |
| Red Hat build of Keycloak 26.6.4 | Versions not published | |
| Red Hat Build of Keycloak | Versions not published | |
| Red Hat Data Grid 8 | Versions not published | |
| Red Hat JBoss Enterprise Application Platform Expansion Pack | Versions not published | |
| Red Hat Single Sign-On 7 | Versions not published |
Other CVEs of Red Hat build of Keycloak 26.6
The 127 CVEs of Red Hat build of Keycloak 26.6 →
CVE-2026-97848
Keycloak-services: keycloak-services: protocol mapper with jsontype=json bypasses token sanitization
6.5
Medium
CVE-2026-97367
Keycloak-services: keycloak-services: dcr azp and sid claim substitution allows account rest session takeover
6.4
Medium
CVE-2026-96547
Keycloak-services: keycloak-services: dcr registration-time claim-path gap allows forging realm_access.roles
6.5
Medium
CVE-2026-96460
Keycloak-services: keycloak-services: indefinite access token renewal via standard token exchange v2
5.4
Medium