Security Advisories

All security advisories for the PowerDNS Authoritative Server are listed here.

• PowerDNS Security Advisory 2022-01: incomplete validation of incoming IXFR transfer in Authoritative Server and Recursor
• PowerDNS Security Advisory 2021-01: Specific query crashes Authoritative Server
• PowerDNS Security Advisory 2020-06: Various issues in our GSS-TSIG support
• PowerDNS Security Advisory 2020-05: Leaking uninitialised memory through crafted zone records
• PowerDNS Security Advisory 2019-06: Denial of service via crafted zone records
• PowerDNS Security Advisory 2019-05: Denial of service via NOTIFY packets
• PowerDNS Security Advisory 2019-04: Denial of service via crafted zone records
• PowerDNS Security Advisory 2019-03: Insufficient validation in the HTTP remote backend
• PowerDNS Security Advisory 2018-05: Packet cache pollution via crafted query
• PowerDNS Security Advisory 2018-03: Crafted zone record can cause a denial of service
• PowerDNS Security Advisory 2018-02: Buffer overflow in dnsreplay
• PowerDNS Security Advisory 2017-04: Missing check on API operations
• PowerDNS Security Advisory 2016-05: Crafted zone record can cause a denial of service
• PowerDNS Security Advisory 2016-04: Insufficient validation of TSIG signatures
• PowerDNS Security Advisory 2016-03: Denial of service via the web server
• PowerDNS Security Advisory 2016-02: Crafted queries can cause abnormal CPU usage
• PowerDNS Security Advisory 2016-01: Crafted queries can cause unexpected backend load
• PowerDNS Security Advisory 2015-03: Packet parsing bug can lead to crashes
• PowerDNS Security Advisory 2015-02: Packet parsing bug can cause thread or process abortion
• PowerDNS Security Advisory 2015-01: Label decompression bug can cause crashes or CPU spikes
• PowerDNS Security Advisory 2012-01: PowerDNS Authoritative Server can be caused to generate a traffic loop
• PowerDNS Security Advisory 2008-03: Some PowerDNS Configurations can be forced to restart remotely
• PowerDNS Security Advisory 2008-02: By not responding to certain queries, domains become easier to spoof

Older security advisories

Version 3.0 of the PowerDNS recursor contains a denial of service bug which can be exploited remotely. This bug, which we believe to only lead to a crash, has been fixed in 3.0.1. There are no guarantees however, so an upgrade from 3.0 is highly recommended.

All versions of PowerDNS before 2.9.21.1 do not respond to certain queries. This in itself is not a problem, but since the discovery by Dan Kaminsky of a new spoofing technique, this silence for queries PowerDNS considers invalid, within a valid domain, allows attackers more chances to feed other resolvers bad data.

All versions of PowerDNS before 2.9.18 contain the following two bugs, which only apply to installations running with the LDAP backend, or installations providing recursion to a limited range of IP addresses. If any of these apply to you, an upgrade is highly advised:

• The LDAP backend did not properly escape all queries, allowing it to fail and not answer questions. We have not investigated further risks involved, but we advise LDAP users to update as quickly as possible (Norbert Sendetzky, Jan de Groot)
• Questions from clients denied recursion could blank out answers to clients who are allowed recursion services, temporarily. Reported by Wilco Baan. This would’ve made it possible for outsiders to blank out a domain temporarily to your users. Luckily PowerDNS would send out SERVFAIL or Refused, and not a denial of a domain’s existence.

All versions of PowerDNS before 2.9.17 are known to suffer from remote denial of service problems which can disrupt operation. Please upgrade to 2.9.17 as this page will only contain detailed security information from 2.9.17 onwards.