Magento have just released (25th June 2019) a number of critical security patches for all supported versions of Magento, including Open Source (formerly Community Edition) and Commerce (formerly Enterprise). The patches also include some performance enhancements and feature fixes which are always welcome too.
You can read about the full details of the Magento 2 release here. There are no less than 75 security enhancements focusing on vulnerabilities in Remote Code Execution (RCE), Cross-Site Scripting (XSS) and other key areas. The full Open Source 2.3.2 release notes are here and include further improvements to speed, payment methods and other core areas of Magento.
SUPEE 11155 details are available here to read and patches the same security areas as the M2 release. Remember that Magento are no longer providing any further features and enhancements for Magento 1, and it is officially end of life as of summer 2020, so the days of these important security releases are numbered.
If you have any concerns about Magento security, or your agency aren't proactive about it, then contact us to see how we provide a professional approach to Magento development and support.