Well, it is that time again. Time for our monthly "Update your servers, NOW," thread. To quote from the deb-sec mailing list

Package : glibc CVE ID : CVE-2015-7547 CVE-2015-8776 CVE-2015-8778 CVE-2015-8779 Debian Bug : 812441 812445 812455

Several vulnerabilities have been fixed in the GNU C Library, glibc.

The first vulnerability listed below is considered to have critical impact.

CVE-2015-7547

The Google Security Team and Red Hat discovered that the glibc host name resolver function, getaddrinfo, when processing AF_UNSPEC queries (for dual A/AAAA lookups), could mismanage its internal buffers, leading to a stack-based buffer overflow and arbitrary code execution. This vulnerability affects most applications which perform host name resolution using getaddrinfo, including system services.

CVE-2015-8776

Adam Nielsen discovered that if an invalid separated time value is passed to strftime, the strftime function could crash or leak information. Applications normally pass only valid time information to strftime; no affected applications are known.

CVE-2015-8778

Szabolcs Nagy reported that the rarely-used hcreate and hcreate_r functions did not check the size argument properly, leading to a crash (denial of service) for certain arguments. No impacted applications are known at this time.

CVE-2015-8779

The catopen function contains several unbound stack allocations (stack overflows), causing it the crash the process (denial of service). No applications where this issue has a security impact are currently known.

While it is only necessary to ensure that all processes are not using the old glibc anymore, it is recommended to reboot the machines after applying the security upgrade.

As usual, our servers have been patched and rebooted. We recommend you do the same.