Ubuntu Security Notice 443-1 – A flaw was discovered in how Firefox handled PASV FTP responses. If a user were tricked into visiting a malicious FTP server, a remote attacker could perform a port-scan of machines within the user’s network, leading to private information disclosure.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/55435/USN-443-1.txt
Source: https://packetstormsecurity.com/files/55435/Ubuntu-Security-Notice-443-1.html