diff --git a/dlls/mshtml/nsio.c b/dlls/mshtml/nsio.c
index d9e822daf5b..9129a557baf 100644
--- a/dlls/mshtml/nsio.c
+++ b/dlls/mshtml/nsio.c
@@ -2488,7 +2488,7 @@ static nsresult NSAPI nsIOService_NewURI(nsIIOService *iface, const nsACString *
     }
 
     nsACString_InitDepend(&spec_str, spec);
-    nsres = nsIIOService_NewURI(nsio, aSpec, aOriginCharset, aBaseURI, &uri);
+    nsres = nsIIOService_NewURI(nsio, &spec_str, aOriginCharset, aBaseURI, &uri);
     nsACString_Finish(&spec_str);
     if(NS_FAILED(nsres))
         TRACE("NewURI failed: %08x\n", nsres);