Based on the email sent by magento (below), please update the according php versions ASAP if possible.

Kind regards,
Jakab András

Magento, An Adobe Company
A vulnerability has recently been discovered in PHP and we recommend Magento Commerce customers adopt changes to address the issue.
MS-ISAC has issued an alert related to multiple vulnerabilities that could allow for arbitrary code execution and a recommendation that all sites using PHP should update to the latest PHP version ASAP ( full alert is available here).

Since Magento Commerce relies on PHP, we recommend that all Merchants using Magento Commerce review necessary updates for PHP with their hosting provider. We also recommend that Merchants complete this review and any updates by September 30 in order to mitigate the vulnerability and to avoid PCI compliance issues that may go into effect as a result of these vulnerabilities at the end of the month. For those using Magento Commerce on our cloud infastructure, please find specific information on these changes here.

Per the alert, recommended patches for this vulnerability include:

PHP 7.1: <a rel="nofollow noreferrer" href="https://www.php.net/ChangeLog-7.php#7.1.32">https://www.php.net/ChangeLog-7.php#7.1.32</a>

PHP 7.2: <a rel="nofollow noreferrer" href="https://www.php.net/ChangeLog-7.php#7.2.22">https://www.php.net/ChangeLog-7.php#7.2.22</a>

PHP 7.3: <a rel="nofollow noreferrer" href="https://www.php.net/ChangeLog-7.php#7.3.9">https://www.php.net/ChangeLog-7.php#7.3.9</a>

If you would like more information on PHP and recent releases, you can visit PHP’s site. And if you have questions or would like more information on best practices for security, please check out our DevBlog article on Security.

Mobile eCommerce is more and more import than before, so many eCommerce will optimize their website for mobile devices, one of the best ways is to develop a new layout for mobile devices.

If the webmaster wants to set Varnish cache for their Magento 2 website and if the website has more than one layout (one layout for a desktop computer, one layout for mobile devices(smartphone, tablet, etc.)), then they need to set mobile device detection for varnish cache.

In our opinion, set varnish mobile device detection for Magento 2 website is very very easy, because of all the necessary info are predefined in the exported VCL for varnish from Magento 2 admin, so we just need to
1. Export VCL file for varnish from Magento 2 admin, and
2. Upload the exported VCL file to the server
to set mobile device detection for varnish cache.

Thank you in advance for your considering to let us set varnish mobile device detection for Magento 2 website.

Best regards,