A problem has been identified in the handling of some types of requests by ActiveX controls installed with Yahoo! Messenger, exposing a remotely exploitable buffer overrun. Because of this, it may be possible for an attacker to execute arbitrary code on a vulnerable host.
Run all software as a nonprivileged user with minimal access rights.
Non-administrative tasks such as browsing the web should always be performed as an unprivileged user with minimal access rights. This will reduce the consequences of successful exploitation of this and other vulnerabilities.
Do not follow links provided by unknown or untrusted sources.
Unless required, do not visit URIs provided by sources of questionable integrity. If required, use additional security precautions through software configuration and privilege management.
Set web browser security to disable the execution of script code or active content.
Modify the default browser security policy to disable potentially dangerous features and eliminate a common vector of client-side attacks.
The vendor has released an update to address this issue: