Live › vulnerability › GHSA-gqj5-2xp5-3qmp
Keycloak's JWT Authorization Grant flow accepts forged assertions because it skips signature verification through algorithm confusion. An attacker with valid client credentials can mint access tokens and impersonate any user linked to the affected identity provider.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-11-03 17:26 UTC. All times on this page are UTC.
Organizations running Keycloak below 26.6.4 as an identity provider, especially with federated identity providers and the JWT Authorization Grant flow. An attacker needs valid client credentials to exploit it. The advisory was withdrawn as a duplicate of GHSA-j97h-3f8r-mrjr, so the canonical record should be checked for final details.
| Product | Ecosystem | Affected | Fixed in |
|---|---|---|---|
| org.keycloak:keycloak-services | maven | < 26.6.4 | 26.6.4 |
26.6.4.26.6.4Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
This advisory has been withdrawn because it is a duplicate of GHSA-j97h-3f8r-mrjr. This link is maintained to preserve external references.
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.
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