The bmexectrans function in kwset.c in grep 2.19 through 2.21 allows local users to cause a denial of service (out-of-bounds heap read and crash) via crafted input when using the -F option.

An integer overflow leading to a heap-based buffer overflow was found in the way grep, A utility used to search through textual input for lines which contain a match to a specified pattern, parsed large lines of data. This flaw could use used to crash grep or potentially execute arbitrary code, if a local user was tricked into running grep on a specially crafted data file.

Patch: http://git.savannah.gnu.org/cgit/grep.git/commit/?id=cbbc1a45b9f843c811905c97c90a5d31f8e6c189 Reference: http://seclists.org/oss-sec/2012/q4/504