A race condition was found in the way the Linux kernel's memory
subsystem handled the copy-on-write (COW) breakage of private read-only
memory mappings. An unprivileged local user could use this flaw to gain
write access to otherwise read-only memory mappings and thus increase
their privileges on the system.
Please refer to http://dirtycow.ninja/ for more information and to keep updated on patches as they are released.