Two issues have been found in PowerDNS Authoritative Server allowing a remote, unauthenticated attacker to cause an abnormal load on the PowerDNS backend by sending crafted DNS queries, which might result in a partial denial of service if the backend becomes overloaded. SQL backends for example are particularly vulnerable to this kind of unexpected load if they have not been dimensioned for it.
The first issue is based on the fact that PowerDNS Authoritative Server accepts queries with a qname's length larger than 255 bytes. This issue has been assigned CVE-2016-5426.
The second issue is based on the fact that PowerDNS Authoritative Server does not properly handle dot inside labels. This issue has been assigned CVE-2016-5427.
PowerDNS Authoritative Server up to and including 3.4.9 is affected. No other versions are affected. The PowerDNS Recursor is not affected.
Created pdns tracking bugs for this issue:
Affects: fedora-23 [bug 1375150]
Affects: epel-all [bug 1375151]