Index: wp-includes/general-template.php
===================================================================
--- wp-includes/general-template.php	(revision 18443)
+++ wp-includes/general-template.php	(working copy)
@@ -270,7 +270,7 @@
 	$args = wp_parse_args( $args, apply_filters( 'login_form_defaults', $defaults ) );
 
 	$form = '
-		<form name="' . $args['form_id'] . '" id="' . $args['form_id'] . '" action="' . site_url( 'wp-login.php', 'login' ) . '" method="post">
+		<form name="' . $args['form_id'] . '" id="' . $args['form_id'] . '" action="' . site_url( 'wp-login.php', 'login_post' ) . '" method="post">
 			' . apply_filters( 'login_form_top', '', $args ) . '
 			<p class="login-username">
 				<label for="' . esc_attr( $args['id_username'] ) . '">' . esc_html( $args['label_username'] ) . '</label>