Updated glibc fixes the following security issues:
A stack overflow (unbounded alloca) could have caused applications which process long strings with the nan function to crash or, potentially, execute arbitrary code (CVE-2014-9761).
A stack-based buffer overflow in getaddrinfo allowed remote attackers to cause a crash or execute arbitrary code via crafted and timed DNS responses (CVE-2015-7547).
Out-of-range time values passed to the strftime function may cause it to crash, leading to a denial of service, or potentially disclosure information (CVE-2015-8776).
Insufficient checking of LDPOINTERGUARD environment variable allowed local attackers to bypass the pointer guarding protection of the dynamic loader on set-user-ID and set-group-ID programs (CVE-2015-8777).
Integer overflow in hcreate and hcreate_r could have caused an out-of-bound memory access. leading to application crashes or, potentially, arbitrary code execution (CVE-2015-8778).
A stack overflow (unbounded alloca) in the catopen function could have caused applications which pass long strings to the catopen function to crash or, potentially execute arbitrary code (CVE-2015-8779).