NLnet Labs ldns 1.2.0 up to and including versions 1.9.0, when used
in applications as (stub) resolver over UDP, lacks matching the
query destination address and port with the response source address
and port. Furthermore not the query ID, neither the question of
the query is matched with that of the response. This makes
applications, that use ldns for (stub) resolver functionality over
UDP, vulnerable for off-path poisoning attacks. The drill tool,
which is shipped with ldns, suffers from this vulnerability.
We would like to thank Pablo Ruiz from codecome.ai for finding and reporting
this vulnerability.