Ubuntu Security Notice 399-1 – A format string vulnerability was discovered in w3m. If a user were tricked into visiting an HTTPS URL protected by a specially crafted SSL certificate, an attacker could execute arbitrary code with user privileges.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/53397/USN-399-1.txt
Source: https://packetstormsecurity.com/files/53397/Ubuntu-Security-Notice-399-1.html