Hundreds of thousands of Virgin Media customers are being urged to change their passwords after one of the firm's routers was found to be vulnerable to hacking.

In an investigation consumer publication Which? discovered the Virgin Media Super Hub 2 router had been set up with a simple password that – if not changed – meant it could be hacked into in just a few days. Once a router has been compromised, hackers could access other devices on a home's network.

Which? set up a 'hackable home' to test the security of a host of gadgets. Within it they used Virgin Media broadband, but it is understood the issue could affect older routers on other networks too – so those with other providers could also need to change passwords.

According to Which? more than 800,000 Virgin Media customers have the Super Hub 2 router and so need to change their router AND Wi-Fi passwords if they are still set as default. See our 30+ Ways to Stop Scams guide for ways to protect yourself online.

I'm a Virgin Media customer – how do I change my password?

Virgin Media provides a number of routers including the Hub 3.0, Super Hub 2ac and Super Hub, as well as the Super Hub 2. To check what type of router you have, look at the sticker on the back.

Virgin Media's website has step-by-step help on how to change your router's password and change your network's password. Your new password should be unique and contain at least 12 characters, with a mixture of upper and lower case letters and numbers.

What does Virgin Media say?

Virgin Media says the risk to customers is small.

A spokesperson said: "The security of our network and of our customers is of paramount importance to us. 

"We continually upgrade our systems and equipment to ensure that we meet all current industry standards. To the extent that technology allows this to be done, we regularly support our customers through advice and updates and offer them the chance to upgrade to a Hub 3.0 which contains additional security provisions."

They refused to say how many customers could be affected.

What about other routers?

Which? and Virgin Media say they believe some other older routers could also be vulnerable, though Virgin Media's router was the only one tested and they haven't specifically identified any other models as being at risk.

If you're worried, or just want to change your password anyway to be on the safe side, here's how to do it with some of the other big providers:

To be clear, there's no suggestion these firms' routers are at any specific risk of hacking.

See our 60-second guide on password security for more info.