Enter a hostname to test the server for CVE-2016-2107.

This test has been discontinued in March 2021. You can use the open-source command line tool or the SSL Labs online test.

Go!

All good, seems fixed or unaffected!

Uh-oh, something went wrong:

IS VULNERABLE.

You can specify a port like this example.com:4433. 443 by default.

To learn more about the vulnerability, read my zero-to-decryption write-up.