diff --git a/src/protocols/vnc/vnc_handlers.c b/src/protocols/vnc/vnc_handlers.c
index 020f2419..cbf0681b 100644
--- a/src/protocols/vnc/vnc_handlers.c
+++ b/src/protocols/vnc/vnc_handlers.c
@@ -141,9 +141,13 @@ void guac_vnc_cursor(rfbClient* client, int x, int y, int w, int h, int bpp) {
     
     pthread_mutex_unlock(&(gc->send_lock));
     
+    pthread_mutex_lock(&(gc->send_lock));
+    
     /* Update cursor */
     guac_protocol_send_cursor(socket, x, y, cursor_layer, 0, 0, w, h);
     
+    pthread_mutex_unlock(&(gc->send_lock));
+    
     /* Free surface */
     cairo_surface_destroy(surface);
     free(buffer);