Index: wp-login.php
===================================================================
--- wp-login.php	(revision 6341)
+++ wp-login.php	(working copy)
@@ -295,7 +295,8 @@
 	else
 		$redirect_to = $_REQUEST['redirect_to'];
 
-	if ( $_POST ) {
+	$http_post = ('POST' == $_SERVER['REQUEST_METHOD']);
+	if ( $http_post ) {
 		$user_login = $_POST['log'];
 		$user_login = sanitize_user( $user_login );
 		$user_pass  = $_POST['pwd'];
@@ -312,7 +313,7 @@
 	do_action_ref_array('wp_authenticate', array(&$user_login, &$user_pass));
 
 	// If cookies are disabled we can't log in even with a valid user+pass
-	if ( $_POST && empty($_COOKIE[TEST_COOKIE]) )
+	if ( $http_post && empty($_COOKIE[TEST_COOKIE]) )
 		$errors['test_cookie'] = __('<strong>ERROR</strong>: WordPress requires Cookies but your browser does not support them or they are blocked.');
 
 	if ( $user_login && $user_pass && empty( $errors ) ) {
@@ -334,9 +335,9 @@
 		}
 	}
 
-	if ( $_POST && empty( $user_login ) )
+	if ( $http_post && empty( $user_login ) )
 		$errors['user_login'] = __('<strong>ERROR</strong>: The username field is empty.');
-	if ( $_POST && empty( $user_pass ) )
+	if ( $http_post && empty( $user_pass ) )
 		$errors['user_pass'] = __('<strong>ERROR</strong>: The password field is empty.');
 
 	// Some parts of this script use the main login form to display a message