diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index 8ac6579..651a17b 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -714,6 +714,18 @@
     /*
      * Secondary checks: always done, but change 'ret' only if it was 0
      */
+    /* keyUsage */
+    if ((mbedtls_x509_crt_check_key_usage(
+             ssl->session_negotiate->peer_cert,
+             MBEDTLS_X509_KU_DIGITAL_SIGNATURE) != 0)) {
+        MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate (usage extensions)"));
+        if (ret == 0) {
+            ret = MBEDTLS_ERR_SSL_BAD_CERTIFICATE;
+        }
+        verify_result |= MBEDTLS_X509_BADCERT_KEY_USAGE;
+    }
+
+    /* extKeyUsage */
     if (ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT) {
         ext_oid = MBEDTLS_OID_SERVER_AUTH;
         ext_len = MBEDTLS_OID_SIZE(MBEDTLS_OID_SERVER_AUTH);
@@ -722,16 +734,14 @@
         ext_len = MBEDTLS_OID_SIZE(MBEDTLS_OID_CLIENT_AUTH);
     }
 
-    if ((mbedtls_x509_crt_check_key_usage(
-             ssl->session_negotiate->peer_cert,
-             MBEDTLS_X509_KU_DIGITAL_SIGNATURE) != 0) ||
-        (mbedtls_x509_crt_check_extended_key_usage(
+    if ((mbedtls_x509_crt_check_extended_key_usage(
              ssl->session_negotiate->peer_cert,
              ext_oid, ext_len) != 0)) {
         MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate (usage extensions)"));
         if (ret == 0) {
             ret = MBEDTLS_ERR_SSL_BAD_CERTIFICATE;
         }
+        verify_result |= MBEDTLS_X509_BADCERT_EXT_KEY_USAGE;
     }
 
     /* mbedtls_x509_crt_verify_with_profile is supposed to report a