CVE-2009-1895

The personality subsystem in the Linux kernel before 2.6.31-rc3 has a
PER_CLEAR_ON_SETID setting that does not clear the ADDR_COMPAT_LAYOUT and
MMAP_PAGE_ZERO flags when executing a setuid or setgid program, which makes
it easier for local users to leverage the details of memory usage to (1)
conduct NULL pointer dereference attacks, (2) bypass the mmap_min_addr
protection mechanism, or (3) defeat address space layout randomization
(ASLR).