Ubuntu Security Notice USN-811-1 – Juan Pablo Lopez Yacubian discovered that Firefox did not properly display invalid URLs. If a user were tricked into accessing a malicious website, an attacker could exploit this to spoof the location bar, such as in a phishing attack. Furthermore, if the malicious website had a valid SSL certificate, Firefox would display the spoofed page as trusted.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/80063/USN-811-1.txt
Source: https://packetstormsecurity.com/files/80063/Ubuntu-Security-Notice-811-1.html