diff --git a/components/tcp_transport/transport_ws.c b/components/tcp_transport/transport_ws.c
index d3acf24430..4d9b7435ac 100644
--- a/components/tcp_transport/transport_ws.c
+++ b/components/tcp_transport/transport_ws.c
@@ -283,7 +283,7 @@ static int ws_connect(esp_transport_handle_t t, const char *host, int port, int
     }
     int header_len = 0;
     do {
-        if ((len = esp_transport_read(ws->parent, ws->buffer + header_len, WS_BUFFER_SIZE - header_len, timeout_ms)) <= 0) {
+        if ((len = esp_transport_read(ws->parent, ws->buffer + header_len, WS_BUFFER_SIZE - 1 - header_len, timeout_ms)) <= 0) {
             ESP_LOGE(TAG, "Error read response for Upgrade header %s", ws->buffer);
             return -1;
         }