(RHSA-2012:1098) Moderate: glibc security and bug fix update

The glibc packages provide the standard C and standard math libraries used
by multiple programs on the system. Without these libraries, the Linux
system cannot function properly.

Multiple errors in glibc’s formatted printing functionality could allow an
attacker to bypass FORTIFY_SOURCE protections and execute arbitrary code
using a format string flaw in an application, even though these protections
are expected to limit the impact of such flaws to an application abort.
(CVE-2012-3404, CVE-2012-3405, CVE-2012-3406)

This update also fixes the following bug:

• A programming error caused an internal array of nameservers to be only
  partially initialized when the /etc/resolv.conf file contained IPv6
  nameservers. Depending on the contents of a nearby structure, this could
  cause certain applications to terminate unexpectedly with a segmentation
  fault. The programming error has been fixed, which restores proper behavior
  with IPv6 nameservers listed in the /etc/resolv.conf file. (BZ#837026)

All users of glibc are advised to upgrade to these updated packages, which
contain backported patches to fix these issues.