From heise.de
An example exploit is available online and works on many standard systems. Admins should quickly install the available updates.
There is a critical security flaw in the Linux tool “sudo” and makes unprivileged users “root”, the system administrator, in no time at all. The reason for the malaise: a bug in the chroot function of sudo. This function is actually intended to “lock” users in their home directory, but allows them to break out of it and extend their rights. An update is available; admins of multi-user systems should act quickly.
The vulnerability exploits a bug in the chroot implementation. Between two function calls, this calls the “Name Service Switch” (NSS), which in turn loads the file /etc/nsswitch.conf. The attacker can now cause this function to load a file he has prepared with C code (a dynamic .so library) and execute it with root rights.