opera -- XMLHttpRequest security bypass

A Secunia Advisory reports:

Secunia Research has discovered a vulnerability in Opera, which can be exploited by malicious people to steal content or to perform actions on other web sites with the privileges of the user.

Normally, it should not be possible for the XMLHttpRequest object to access resources from outside the domain of which the object was opened. However, due to insufficient validation of server side redirects, it is possible to circumvent this restriction.

[source]