Race condition in the tty_fasync function in drivers/char/tty_io.c in the Linux kernel before 2.6.32.6 allows local users to cause a denial of service (NULL pointer dereference and system crash) or possibly have unspecified other impact via unknown vectors, related to the put_tty_queue and __f_setown functions. NOTE: the vulnerability was addressed in a different way in 2.6.32.9.
http://www.debian.org/security/2010/dsa-2094
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.32.6
http://www.openwall.com/lists/oss-security/2010/06/15/2
http://www.openwall.com/lists/oss-security/2010/06/15/3
http://www.openwall.com/lists/oss-security/2010/06/15/4
http://www.openwall.com/lists/oss-security/2010/06/15/5
http://www.ubuntu.com/usn/USN-1000-1