diff --git a/library/ssl_tls12_server.c b/library/ssl_tls12_server.c
index 05a5767..5aa541b 100644
--- a/library/ssl_tls12_server.c
+++ b/library/ssl_tls12_server.c
@@ -3203,6 +3203,12 @@
 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
     if( mbedtls_ssl_ciphersuite_uses_server_signature( ciphersuite_info ) )
     {
+        if( dig_signed == NULL )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+            return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+        }
+
         size_t dig_signed_len = ssl->out_msg + ssl->out_msglen - dig_signed;
         size_t hashlen = 0;
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
@@ -3241,12 +3247,6 @@
          */
         if( md_alg != MBEDTLS_MD_NONE )
         {
-            if( dig_signed == NULL )
-            {
-                MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
-                return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
-            }
-
             ret = mbedtls_ssl_get_key_exchange_md_tls1_2( ssl, hash, &hashlen,
                                                           dig_signed,
                                                           dig_signed_len,