EDIT: From AWS (https://aws.amazon.com/security/security-bulletins/cve-2015-...):
""" We have reviewed the issues described in CVE-2015-7547 and have determined that AWS Services are largely not affected. The only exception is customers using Amazon EC2 who’ve modified their configurations to use non-AWS DNS infrastructure should update their Linux environments immediately following directions provided by their Linux distribution. EC2 customers using the AWS DNS infrastructure are unaffected and don’t need to take any action. """