Ubuntu Security Notice 3239-3 - USN-3239-1 fixed vulnerabilities in the GNU C Library. Unfortunately, the fix for CVE-2016-3706 introduced a regression that in some circumstances prevented IPv6 addresses from resolving. This update reverts the change in Ubuntu 12.04 LTS.
5ac6541ec2d8b1c23c092a5bf72c90784949c38ff1917bcec981e9c9d84897c2