Ubuntu Security Notice USN-747-1 – It was discovered that libicu did not correctly handle certain invalid encoded data. If a user or automated system were tricked into processing specially crafted data with applications linked against libicu, certain content filters could be bypassed.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/76128/USN-747-1.txt
Source: https://packetstormsecurity.com/files/76128/Ubuntu-Security-Notice-747-1.html