diff --git a/dlls/urlmon/tests/sec_mgr.c b/dlls/urlmon/tests/sec_mgr.c
index 2f33f02ef2c..2509d84c575 100644
--- a/dlls/urlmon/tests/sec_mgr.c
+++ b/dlls/urlmon/tests/sec_mgr.c
@@ -423,8 +423,8 @@ static void test_SecurityManager(void)
     ok(size == sizeof(secid10) ||
        size == sizeof(secid10_2), /* win2k3 */
        "size=%d\n", size);
-    ok(!memcmp(buf, secid10, size) ||
-       !memcmp(buf, secid10_2, size), /* win2k3 */
+    ok(!memcmp(buf, secid10, sizeof(secid10)) ||
+       !memcmp(buf, secid10_2, sizeof(secid10_2)), /* win2k3 */
        "wrong secid\n");
 
     zone = 100;