Important: glibc security update

Updated glibc packages that fix three security issues are now available for
Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having
important security impact. Common Vulnerability Scoring System (CVSS) base
scores, which give detailed severity ratings, are available for each
vulnerability from the CVE links in the References section.

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

The fix for CVE-2010-3847 introduced a regression in the way the dynamic
loader expanded the $ORIGIN dynamic string token specified in the RPATH and
RUNPATH entries in the ELF library header. A local attacker could use this
flaw to escalate their privileges via a setuid or setgid program using
such a library. (CVE-2011-0536)

It was discovered that the glibc fnmatch() function did not properly
restrict the use of alloca(). If the function was called on sufficiently
large inputs, it could cause an application using fnmatch() to crash or,
possibly, execute arbitrary code with the privileges of the application.
(CVE-2011-1071)

It was discovered that the locale command did not produce properly escaped
output as required by the POSIX specification. If an attacker were able to
set the locale environment variables in the environment of a script that
performed shell evaluation on the output of the locale command, and that
script were run with different privileges than the attacker's, it could
execute arbitrary code with the privileges of the script. (CVE-2011-1095)

All users should upgrade to these updated packages, which contain
backported patches to correct these issues.

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/kb/docs/DOC-11259

625893 - CVE-2011-1095 glibc: insufficient quoting in the locale command output
667974 - CVE-2011-0536 glibc: CVE-2010-3847 fix causes linker to search CWD when running privileged program with $ORIGIN in R*PATH
681054 - CVE-2011-1071 glibc: fnmatch() alloca()-based memory corruption flaw

https://www.redhat.com/security/data/cve/CVE-2011-0536.html
https://www.redhat.com/security/data/cve/CVE-2011-1071.html
https://www.redhat.com/security/data/cve/CVE-2011-1095.html
https://www.redhat.com/security/data/cve/CVE-2011-1658.html
https://www.redhat.com/security/data/cve/CVE-2011-1659.html
https://access.redhat.com/security/updates/classification/#important