Index: src/wp-includes/functions.php
===================================================================
--- src/wp-includes/functions.php	(revision 25433)
+++ src/wp-includes/functions.php	(working copy)
@@ -3233,26 +3233,31 @@
 	if ( defined('WP_SITEURL') && '' != WP_SITEURL ) {
 		$url = WP_SITEURL;
 	} else {
+		$abspath_fix = str_replace( '\\', '/', ABSPATH );
+		$script_filename_dir = dirname( $_SERVER['SCRIPT_FILENAME'] );
+
 		// The request is for the admin
 		if ( strpos( $_SERVER['REQUEST_URI'], 'wp-admin' ) !== false || strpos( $_SERVER['REQUEST_URI'], 'wp-login.php' ) !== false ) {
 			$path = preg_replace( '#/(wp-admin/.*|wp-login.php)#i', '', $_SERVER['REQUEST_URI'] );
 
 		// The request is for a file in ABSPATH
-		} elseif ( dirname( $_SERVER['SCRIPT_FILENAME'] ) . '/' == ABSPATH ) {
+		} elseif ( $script_filename_dir . '/' == $abspath_fix ) {
 			// Strip off any file/query params in the path
 			$path = preg_replace( '#/[^/]*$#i', '', $_SERVER['PHP_SELF'] );
 
 		} else {
-			if ( false !== strpos( $_SERVER['SCRIPT_FILENAME'], ABSPATH ) ) {
+			if ( false !== strpos( $_SERVER['SCRIPT_FILENAME'], $abspath_fix ) ) {
 				// Request is hitting a file inside ABSPATH
-				$directory = str_replace( ABSPATH, '', dirname( $_SERVER['SCRIPT_FILENAME'] ) );
+				$directory = str_replace( ABSPATH, '', $script_filename_dir );
 				// Strip off the sub directory, and any file/query paramss
 				$path = preg_replace( '#/' . preg_quote( $directory, '#' ) . '/[^/]*$#i', '' , $_SERVER['REQUEST_URI'] );
-			} else {
+			} elseif ( false !== strpos( $abspath_fix, $script_filename_dir ) ) {
 				// Request is hitting a file above ABSPATH
-				$subdirectory = str_replace( dirname( $_SERVER['SCRIPT_FILENAME'] ), '', ABSPATH );
+				$subdirectory = str_replace( $script_filename_dir, '', $abspath_fix );
 				// Strip off any file/query params from the path, appending the sub directory to the install
 				$path = preg_replace( '#/[^/]*$#i', '' , $_SERVER['REQUEST_URI'] ) . $subdirectory;
+			} else {
+				$path = preg_replace( '#/(wp-admin/.*|wp-login.php)#i', '', $_SERVER['REQUEST_URI'] );
 			}
 		}