Multiple vulnerabilities have been discovered in pdns, an authoritative DNS server. The Common Vulnerabilities and Exposures project identifies the following problems:

CVE-2016-2120 Mathieu Lafon discovered that pdns does not properly validate records in zones. An authorized user can take advantage of this flaw to crash server by inserting a specially crafted record in a zone under their control and then sending a DNS query for that record.

CVE-2016-7068 Florian Heinz and Martin Kluge reported that pdns parses all records present in a query regardless of whether they are needed or even legitimate, allowing a remote, unauthenticated attacker to cause an abnormal CPU usage load on the pdns server, resulting in a partial denial of service if the system becomes overloaded.

CVE-2016-7072 Mongo discovered that the webserver in pdns is susceptible to a denial-of-service vulnerability, allowing a remote, unauthenticated attacker to cause a denial of service by opening a large number of TCP connections to the web server.

CVE-2016-7073 / CVE-2016-7074 Mongo discovered that pdns does not sufficiently validate TSIG signatures, allowing an attacker in position of man-in-the-middle to alter the content of an AXFR.

For the stable distribution (jessie), these problems have been fixed in version 3.4.1-4+deb8u7.

For the unstable distribution (sid), these problems have been fixed in version 4.0.2-1.

We recommend that you upgrade your pdns packages.