Description:
Sergio Alvarez has reported a vulnerability in avast!, which can be exploited by malicious people to compromise a vulnerable system.

The vulnerability is caused due to an error within the parsing of .CAB files and can be exploited to cause a heap-based buffer overflow via a specially crafted .CAB file.

Successful exploitation may allow execution of arbitrary code.

The vulnerability reportedly affects versions prior to 4.7.766 for servers and 4.7.700 for the Managed Client product.

Solution:
Update to the latest versions.
http://www.avast.com/eng/download.html

Secunia Advisory