VirtualPC_Services in Microsoft Virtual PC for Mac 6.0 through 6.1 allows local attackers to truncate and overwrite arbitrary files, and execute arbitrary code, via a symlink attack on the VPCServices_Log temporary file.
Atstake Security Advisory A021004-1 - Both Connectix Virtual PC 6.0.x and Microsoft Virtual PC 6.1 on Mac OS X suffer from an insecure temporary file creation vulnerability.