Red Hat: RHSA-2011:0413-01 Critical Security Alert for glibc Flaws

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.