diff --git a/dlls/urlmon/sec_mgr.c b/dlls/urlmon/sec_mgr.c
index 609ca4f7ddd..52e29b64a28 100644
--- a/dlls/urlmon/sec_mgr.c
+++ b/dlls/urlmon/sec_mgr.c
@@ -251,8 +251,10 @@ static HRESULT WINAPI SecManagerImpl_MapUrlToZone(IInternetSecurityManager *ifac
             return hres;
     }
 
-    if(!pwszUrl)
+    if(!pwszUrl) {
+        *pdwZone = -1;
         return E_INVALIDARG;
+    }
 
     if(dwFlags)
         FIXME("not supported flags: %08x\n", dwFlags);
diff --git a/dlls/urlmon/tests/misc.c b/dlls/urlmon/tests/misc.c
index c93d6c201d3..b6f642187cc 100644
--- a/dlls/urlmon/tests/misc.c
+++ b/dlls/urlmon/tests/misc.c
@@ -691,7 +691,7 @@ static void test_SecurityManager(void)
     zone = 100;
     hres = IInternetSecurityManager_MapUrlToZone(secmgr, NULL, &zone, 0);
     ok(hres == E_INVALIDARG, "MapUrlToZone failed: %08x, expected E_INVALIDARG\n", hres);
-    ok(zone == 100, "zone=%d\n", zone);
+    ok(zone == 100 || zone == -1, "zone=%d\n", zone);
 
     size = sizeof(buf);
     hres = IInternetSecurityManager_GetSecurityId(secmgr, NULL, buf, &size, 0);