There have been some interesting exploits out and about, and often sysadmins have a lot of wordpress installs going on the one machine. This can be problematic when it comes to upgrading multiple instances.
So I posted a script up on the Rimuhosting blog that should fix this
wget http://b.ri.mu/files/wordpress-upgrade-patched.sh
sh wordpress-upgrade-patch.sh
Original Article: http://blog.rimuhosting.com/2009/08/20/wordpress-upgrade-script/