Ubuntu Security Notice 955-1 – Maksymilian Arciemowicz and Adam Zabrocki discovered that OPIE incorrectly handled long usernames. A remote attacker could exploit this with a crafted username and make applications linked against libopie crash, leading to a denial of service.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/90904/USN-955-1.txt
Source: https://packetstormsecurity.com/files/90904/Ubuntu-Security-Notice-955-1.html