Ubuntu Security Notice USN-816-1 – Moxie Marlinspike discovered that fetchmail did not properly handle certificates with NULL characters in the certificate name. A remote attacker could exploit this to perform a man in the middle attack to view sensitive information or alter encrypted communications.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/80310/USN-816-1.txt
Source: https://packetstormsecurity.com/files/80310/Ubuntu-Security-Notice-816-1.html