CVE 2009-1337
The exit_notify function in kernel/exit.c in the Linux kernel before 2.6.30-rc1 does not restrict exit signals when the CAP_KILL capability is held, which allows local users to send an arbitrary signal to a process by running a program that modifies the exit_signal field and then uses an exec system call to launch a setuid application.
See the 
CVE page on Mitre.org
for more details.
