The glibc packages provide the standard C libraries (libc), POSIX thread libraries (libpthread), standard math libraries (libm), and the Name Server Caching Daemon (nscd) used by multiple programs on the system. Without these libraries, the Linux system cannot function correctly.
An invalid free flaw was found in glibc's getaddrinfo() function when used with the AI_IDN flag. A remote attacker able to make an application call this function could use this flaw to execute arbitrary code with the permissions of the user running the application. Note that this flaw only affected applications using glibc compiled with libidn support. (CVE-2013-7424)
All glibc users are advised to upgrade to these updated packages, which contain a backported patch to correct this issue.