This blog post is 9 years old and may be out of date.
Mullvad is safe against the 'Port Fail' attack
A few days ago Perfect Privacy presented a vulnerability that affects many VPN providers offering port forwarding for their customers. According to their post five of the nine tested VPN providers were vulnerable to this attack.
Mullvad is not affected by this vulnerability. We have used a dual IP setup protecting against this attack since 2010.