diff --git a/vnc.c b/vnc.c
index c0700c0..1652029 100644
--- a/vnc.c
+++ b/vnc.c
@@ -2438,6 +2438,10 @@
 {
     VncDisplay *vs = ds ? (VncDisplay *)ds->opaque : vnc_display;
 
+    if (!vs) {
+        return -1;
+    }
+
     if (vs->password) {
 	qemu_free(vs->password);
 	vs->password = NULL;