Integer overflow in the fcount counter in FreeBSD before 4.2 through 5.0 allows local users to cause a denial of service (crash) and possibly execute arbitrary code via multiple calls to (1) fpathconf and (2) lseek, which do not properly decrement fcount through a call to fdrop.

Race condition in exec in OpenBSD 4.0 and earlier, NetBSD 1.5.2 and earlier, and FreeBSD 4.4 and earlier allows local users to gain privileges by attaching a debugger to a process before the kernel has determined that the process is setuid or setgid.

FreeBSD 5.x, 4.x, and 3.x allows local users to cause a denial of service by executing a program with a malformed ELF image header.

FreeBSD, NetBSD, and OpenBSD allow an attacker to cause a denial of service by creating a large number of socket pairs using the socketpair function, setting a large buffer size via setsockopt, then writing large buffers.