This flaw only affects specific, non-default configurations of sudo, in which sudoers configuration entry allows a user to run a command as any user except root, for example:
bob myhost = (ALL, !root) /usr/bin/vi
This configuration allows user bob to run vi command as any other user except root. However, this flaw also allows bob to run the vi command as root by specifying the target user using the numeric id of -1. Only the specified command can be run, this flaw does NOT allow user to run other commands that those specified in the sudoers configuration.
Any other configurations of sudo (including configurations that allow user to run commands as any user including root and configurations that allow user to run command as a specific other user) are NOT affected by this flaw.