get only first certificate from header (#215)

Author: gerbrand-bosch

app/services/mtls_service.py

@@ -61,7 +61,11 @@ def get_mtls_cert(self, request: Request) -> bytes:
                 status_code=401,
                 detail="Missing client certificate",
             )
-        return request.headers[self._SSL_CLIENT_CERT_HEADER_NAME].encode("ascii")
+        return (
+            request.headers[self._SSL_CLIENT_CERT_HEADER_NAME]
+            .split(",")[0]
+            .encode("ascii")
+        )
 
     def get_mtls_pub_key(self, request: Request) -> str:
         """