This vulnerability affects the Samba distcc module, and also Apple Xcode which uses the distcc module for distributed compiling. There are known exploits for distcc which which make it possible for a remote attacker to gain full user level access.
All versions of Samba distcc.
System compromise, arbitrary command execution.
Configure distcc for greater security, see http://distcc.samba.org/security.html
Restrict network access.