The flaw could allow a hacker to access forum user’s personal data

A serious flaw in software widely used to power online discussion sites could allow hackers to harvest reams of personal data, the BBC has learned.

The flaw in a specific version of the vBulletin software allows anyone to easily access the main administrator username and password for a site.

This would also allow hackers to access data, such as e-mail addresses, and edit the site at will.

The owner of the program – Internet Brands – released a fix on 21 July.

However, at time of writing, many sites remain vulnerable.