Race condition in Linux 2.6, when threads are sharing memory mapping via CLONE_VM (such as linuxthreads and vfork), might allow local users to cause a denial of service (deadlock) by triggering a core dump while waiting for a thread that has just performed an exec.
http://www.ubuntu.com/usn/usn-199-1
http://www.mandriva.com/security/advisories?name=MDKSA-2006:072