The Heartbleed bug is a severe OpenSSL vulnerability in the cryptographic software library. This allows exposing sensitive information over SSL/TLS encryption for applications like web, email, IM, and VPN. Fixing the bug is quite straightforward. Upgrade OpenSSL to 1.0.1g or higher version. Fix the CSR using an upgraded version of OpenSSL and get it signed by a certificate authority. Implement that on your respective web servers or edge devices. Fix the bug using a signed certificate is simple.”]
Source: https://geekflare.com/how-to-test-heart-bleed-ssl-vulnerabilities-cve-2014-0160/