diff --git a/components/mbedtls/library/ssl_cli.c b/components/mbedtls/library/ssl_cli.c
index a2b9f8cfe1..c0ade43ad9 100644
--- a/components/mbedtls/library/ssl_cli.c
+++ b/components/mbedtls/library/ssl_cli.c
@@ -2473,7 +2473,7 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
         sig_len = ( p[0] << 8 ) | p[1];
         p += 2;
 
-        if( end != p + sig_len )
+        if( p != end - sig_len )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
             mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,