O2 has warned customers that a flaw in its home broadband routers could leave them vulnerable to having their personal information stolen.
The internet service provider is currently working on a fix for the vulnerability, which could also allow hackers to take control of effected systems, with router manufacturer Thomson.
Although it hasn't elaborated on the details of the cross-site request forgery issue, the broadband supplier said in a statement that it was working with Paul Mutton, the individual who first discovered the flaw.
"This flaw allows remote attackers to take almost full control of the router, including stealing the wireless encryption key and forwarding external ports to internal IP addresses," Mr Mutton wrote on his blog.
He added that he would not go into greater detail about the flaw until O2 had fully addressed the issue.
Earlier this week, O2 launched a new deal offering three months of free home broadband to new customers.