The MITRE CVE dictionary describes this issue as:
Integer overflow in the phar_parse_tarfile function in tar.c in the phar extension in PHP before 5.3.14 and 5.4.x before 5.4.4 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted tar file that triggers a heap-based buffer overflow.
Find out more about CVE-2012-2386 from the
MITRE CVE dictionary dictionary and
This issue did not affect the version of php as shipped with Red Hat Enterprise Linux 5 as it did not include support for phar extension yet. This issue was addressed in php53 package for Red Hat Enterprise Linux 5 via RHSA-2012:1047 and in php package for Red Hat Enterprise Linux 6 via RHSA-2012:1046.