Title: Version 3.9.23
Published: May 13, 2019

---

# Version 3.9.23

## In this article

 * [Installation/Update Information](https://wordpress.org/documentation/wordpress-version/version-3-9-23/?output_format=md#installation-update-information)
 * [Summary](https://wordpress.org/documentation/wordpress-version/version-3-9-23/?output_format=md#summary)
 * [List of Files Revised](https://wordpress.org/documentation/wordpress-version/version-3-9-23/?output_format=md#list-of-files-revised)

[ Back to top](https://wordpress.org/documentation/wordpress-version/version-3-9-23/?output_format=md#wp--skip-link--target)

On 16 January, 2018, WordPress 3.9.23 was released to the public.

## 󠀁[Installation/Update Information](https://wordpress.org/documentation/wordpress-version/version-3-9-23/?output_format=md#installation-update-information)󠁿

To download WordPress 3.9.23, update automatically from the Dashboard > Updates 
menu in your site’s admin area or visit [https://wordpress.org/download/release-archive/](https://wordpress.org/download/release-archive/).

For step-by-step instructions on installing and updating WordPress:

 *  [Updating WordPress](https://wordpress.org/documentation/article/updating-wordpress/)

If you are new to WordPress, we recommend that you begin with the following:

 *  [New To WordPress – Where to Start](https://wordpress.org/support/article/new_to_wordpress_-_where_to_start/?output_format=md)
 *  [First Steps With WordPress](https://wordpress.org/support/article/first-steps-with-wordpress/?output_format=md)
   or [Upgrading WordPress Extended](https://wordpress.org/documentation/article/upgrading-wordpress-extended-instructions/)
 *  [WordPress Lessons](https://wordpress.org/support/article/wordpress-lessons/?output_format=md)

## 󠀁[Summary](https://wordpress.org/documentation/wordpress-version/version-3-9-23/?output_format=md#summary)󠁿

From the [WordPress 4.9.2 release post](https://wordpress.org/news/2018/01/wordpress-4-9-2-security-and-maintenance-release/):
WordPress versions 4.9 and earlier are affected by an XSS vulnerability in the Flash
fallback files in MediaElement 4.x. The following fixes have been implemented in
this release:

 1. Upgrade: When deleting old files, if deletion fails attempt to empty the file instead.(
    [#42963](https://core.trac.wordpress.org/ticket/42963))
 2. External Libraries: Remove unnecessary / obsoleted MediaElement.js files. ([#42720](https://core.trac.wordpress.org/ticket/42720))

## 󠀁[List of Files Revised](https://wordpress.org/documentation/wordpress-version/version-3-9-23/?output_format=md#list-of-files-revised)󠁿

    ```wp-block-preformatted
    wp-admin/includes/update-core.php
    wp-admin/about.php
    wp-includes/version.php
    wp-includes/js/mediaelement/flashmediaelement.swf
    wp-includes/js/mediaelement/silverlightmediaelement.xap
    ```

First published

May 13, 2019

Last updated