Thankfully, this isn't a remote access exploit that a Blaster or Sasser like worm could exploit, but it could be triggered by an email or IM if POSIX services are enabled.

This is probably low-risk, but all Windows users should patch, patch, patch ... This new exploit code mainly illustrates "reverse engineering" is in process. The one's I'm most concerned about are MS04-022 and MS04-024, so it's important to "patch the roof before it rains" and perform a Windows update now

MS04-020 - POSIX Exploit developed
http://www.incidents.org/diary.php?date=2004-07-16

The ISC was notified earlier today that there was a public release of a Windows POSIX local privilege escalation exploit (MS04-020). Time to patch was last Tuesday. This is not a remote access issue, but one that still needs to be addressed and corrected.