diff --git a/unix/vncviewer/CConn.cxx b/unix/vncviewer/CConn.cxx
index 8231f4c..efc3c33 100644
--- a/unix/vncviewer/CConn.cxx
+++ b/unix/vncviewer/CConn.cxx
@@ -221,8 +221,8 @@
   PasswdDialog dlg(dpy, title.buf, !user);
   if (!dlg.show()) throw rfb::Exception("Authentication cancelled");
   if (user)
-    *user = strDup(dlg.userEntry.getText());
-  *password = strDup(dlg.passwdEntry.getText());
+    *user = safe_strdup(dlg.userEntry.getText());
+  *password = safe_strdup(dlg.passwdEntry.getText());
 }