A query with a specific set of characteristics could cause a server using DNS64 to encounter an assertion failure and terminate. An attacker could deliberately construct a query, enabling denial-of-service against a server if it was configured to use the DNS64 feature and other preconditions were met. Servers are at risk if they are configured to use DNS64 and if the option "break-dnssec yes;" is in use. External References: https://kb.isc.org/article/AA-01465 Mitigation: Servers which have configurations which require DNS64 and "break-dnssec yes;" should upgrade. Servers which are not using these features in conjunction are not at risk from this defect.
Acknowledgments: Name: ISC Upstream: Oleg Gorokhov (Yandex)
Created bind tracking bugs for this issue: Affects: fedora-all [bug 1441916]
Created bind99 tracking bugs for this issue: Affects: fedora-all [bug 1441917]
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2017:1095 https://access.redhat.com/errata/RHSA-2017:1095
This issue has been addressed in the following products: Red Hat Enterprise Linux 6 Via RHSA-2017:1105 https://access.redhat.com/errata/RHSA-2017:1105