A vulnerability allows attackers to execute arbitrary code on vulnerable installations of Samba. User interaction is not required to exploit this vulnerability. The specific flaw exists in the parsing of RPC requests to the SPOOLSS RPC interface. When parsing a request to RFNPCNEX, heap allocation is calculated based on user input. By specifying invalid values, heap blocks can be overwritten leading to remote code execution.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/56805/ZDI-07-031.txt
Source: https://packetstormsecurity.com/files/56805/Zero-Day-Initiative-Advisory-07-031.html