Red Hat Enterprise Linux 7: RHSA-2015:2111-07 Low: grep Buffer Overflow

The grep utility searches through textual input for lines that contain a match to a specified pattern and then prints the matching lines. The GNU grep utilities include grep, egrep, and fgrep.
A heap-based buffer overflow flaw was found in the way grep processed certain pattern and text combinations. An attacker able to trick a user into running grep on specially crafted input could use this flaw to crash grep or, potentially, read from uninitialized memory. (CVE-2015-1345)
This update also fixes the following bugs:
* Prior to this update, the w and W symbols were inconsistently matched to the [:alnum:] character class. Consequently, using regular expressions with "w" and "W" could lead to incorrect results. With this update, "w" is consistently matched to the [_[:alnum:]] character, and "W" is consistently matched to the [^_[:alnum:]] character. (BZ#1159012)
* Previously, the Perl Compatible Regular Expression (PCRE) matcher (selected by the "-P" parameter in grep) did not work correctly when matching non-UTF-8 text in UTF-8 locales. Consequently, an error message about invalid UTF-8 byte sequence characters was returned. To fix this bug, patches from upstream have been applied to the grep utility. As a result, PCRE now skips non-UTF-8 characters as non-matching text without returning any error message. (BZ#1217080)
All grep users are advised to upgrade to these updated packages, which contain backported patches to correct these issues.