dnsmasq -- cache poisoning vulnerability in certain configurations

Simon Kelley reports:

    [In configurations where the forwarding server address contains an @
    character for specifying a sending interface or source address, the]
    random source port behavior was disabled, making cache poisoning
    attacks possible.
  


  This only affects configurations of the form server=1.1.1.1@em0 or
  [email protected], i. e. those that specify an interface to
  send through, or an IP address to send from, or use together with
  NetworkManager.