diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 2cab41acd7..2390adca33 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -2043,8 +2043,10 @@ function get_allowed_mime_types( $user = null ) {
 	$t = wp_get_mime_types();
 
 	unset( $t['swf'], $t['exe'] );
-	$unfiltered = $user ? user_can( $user, 'unfiltered_html' ) : current_user_can( 'unfiltered_html' );
-	if ( ! $unfiltered )
+	if ( function_exists( 'current_user_can' ) )
+		$unfiltered = $user ? user_can( $user, 'unfiltered_html' ) : current_user_can( 'unfiltered_html' );
+
+	if ( empty( $unfiltered ) )
 		unset( $t['htm|html'] );
 
 	return apply_filters( 'upload_mimes', $t, $user );