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-2016-2120). 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-2016-7068). Mongo discovered that the webserver in pdns is susceptible to a denial-of-service vulnerability. A remote, unauthenticated attacker to cause a denial of service by opening a large number of f TCP connections to the web server (CVE-2016-7072). 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 (CVE-2016-7073, CVE-2016-7074).