When a Keycloak server is configured to support mTLS authentication for OAuth/OpenID clients, it does not properly verify the client certificate chain. A client that possesses a proper certificate can authorize itself as any other client and therefore access data that belongs to other clients.
{
"nvd_published_at": "2023-10-04T11:15:10Z",
"github_reviewed_at": "2023-06-30T20:31:37Z",
"severity": "HIGH",
"cwe_ids": [
"CWE-295"
],
"github_reviewed": true
}