diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index a02b712..7ee9883 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -711,6 +711,9 @@
     unsigned char verify_cookie_len;    /*!<  Cli: cookie length for
                                          *    dtls / tls 1.3
                                          *    Srv: flag for sending a cookie */
+    uint16_t hrr_cookie_len;       /*!<  Cli: hrr cookie length for
+                                         *    dtls / tls 1.3
+                                         *    Srv: unused                    */
 #endif /* MBEDTLS_SSL_PROTO_DTLS || MBEDTLS_SSL_PROTO_TLS1_3 */
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)