O2: Sharing your mobile number with every website you visit
Hello there reader. Guess what? If you happen to be reading this frankly brilliant article on your O2 mobile phone, you'll be thrilled to bursting point to learn that O2 have already sent us your mobile phone number within the HTTP headers which normally contain information about how content can be displayed on your device.
Alas, these headers aren't usually seen by users and don't tend to be logged by sites, however, this clanger of a flaw will absolutely allow malicious sites to get some of that lovely personal information of yours.
How bad is this? Well, should you open an email on your O2 phone, and say, read a message which includes external images, simply opening the mail would divulge your phone number. Of course, that could then be used in a phishing attack or some other lousy scam.
This was uncovered by @lewispeckover and the problem is still affecting many smartphones. If you're a user of an O2 phone and want to check if you're being affected, then visit Lewis Peckover's website to find out more.
We strongly suspect a lot of ranting and swearing from the Twitter community over this.
EDIT: As of 2pm today (25th January), this 'glitch' has been fixed. In a blog post, O2 say that it has been going on since 10th January.