Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 12570)
+++ wp-includes/functions.php	(working copy)
@@ -1107,8 +1107,7 @@
 /**
  * Check content for video and audio links to add as enclosures.
  *
- * Will not add enclosures that have already been added and will
- * remove enclosures that are no longer in the post. This is called as
+ * Will not add enclosures that have already been added. This is called as
  * pingbacks and trackbacks.
  *
  * @package WordPress
@@ -1139,15 +1138,6 @@
 	debug_fwrite( $log, 'Post contents:' );
 	debug_fwrite( $log, $content . "\n" );
 
-	foreach ( $pung as $link_test ) {
-		if ( !in_array( $link_test, $post_links_temp[0] ) ) { // link no longer in post
-			$mid = $wpdb->get_col( $wpdb->prepare("SELECT meta_id FROM $wpdb->postmeta WHERE post_id = %d AND meta_key = 'enclosure' AND meta_value LIKE (%s)", $post_ID, $link_test . '%') );
-			do_action( 'delete_postmeta', $mid );
-			$wpdb->query( $wpdb->prepare("DELETE FROM $wpdb->postmeta WHERE post_id IN(%s)", implode( ',', $mid ) ) );
-			do_action( 'deleted_postmeta', $mid );
-		}
-	}
-
 	foreach ( (array) $post_links_temp[0] as $link_test ) {
 		if ( !in_array( $link_test, $pung ) ) { // If we haven't pung it already
 			$test = parse_url( $link_test );
@@ -1162,12 +1152,12 @@
 		if ( $url != '' && !$wpdb->get_var( $wpdb->prepare( "SELECT post_id FROM $wpdb->postmeta WHERE post_id = %d AND meta_key = 'enclosure' AND meta_value LIKE (%s)", $post_ID, $url . '%' ) ) ) {
 			if ( $headers = wp_get_http_headers( $url) ) {
 				$len = (int) $headers['content-length'];
-				$type = $headers['content-type'];
+				$type = $wpdb->escape( $headers['content-type'] );
 				$allowed_types = array( 'video', 'audio' );
 				if ( in_array( substr( $type, 0, strpos( $type, "/" ) ), $allowed_types ) ) {
 					$meta_value = "$url\n$len\n$type\n";
-					$wpdb->insert($wpdb->postmeta, array('post_id' => $post_ID, 'meta_key' => 'enclosure', 'meta_value' => $meta_value) );
-					do_action( 'added_postmeta', $wpdb->insert_id, $post_ID, 'enclosure', $meta_value );
+					$wpdb->query( $wpdb->prepare( "INSERT INTO `$wpdb->postmeta` ( `post_id` , `meta_key` , `meta_value` )
+					VALUES ( %d, 'enclosure' , %s)", $post_ID, $meta_value ) );
 				}
 			}
 		}