diff --git a/wp-includes/media.php b/wp-includes/media.php
index 282e68a0c5..9c04e9c7ac 100644
--- a/wp-includes/media.php
+++ b/wp-includes/media.php
@@ -3409,6 +3409,16 @@ function attachment_url_to_postid( $url ) {
 	);
 	$post_id = $wpdb->get_var( $sql );
 
+	/**
+	 * Filter an attachment id found by URL.
+	 *
+	 * @since 4.2.0
+	 *
+	 * @param int|null $post_id  The post_id (if any) found by the function.
+	 * @param string   $url      The URL being looked up.
+	 */
+	$post_id = apply_filters( 'attachment_url_to_postid', $post_id, $url );
+
 	return (int) $post_id;
 }
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 96f0d3433d..d7d6b05ea5 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-beta2-31866';
+$wp_version = '4.2-beta2-31867';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.