Ubuntu Security Notice USN-829-1 – It was discovered that Qt did not properly handle certificates with NULL characters in the Subject Alternative Name field of X.509 certificates. An 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/81202/USN-829-1.txt
Source: https://packetstormsecurity.com/files/81202/Ubuntu-Security-Notice-829-1.html