/ 
Net-DNS-0.75_1
/ Net::DNS::Resolver::Recurse
Security Advisories (2)
CVE-2026-64193 (2026-07-20)

Net::DNS versions through 1.55 for Perl allow remote execution injection via EDNS EXTENDED ERROR. Net::DNS::RR::OPT::EXTENDED_ERROR::_decompose parses the EXTRA-TEXT field of an EDNS EXTENDED-ERROR option (RFC 8914) by tokenising the raw bytes and passing the result to Perl's eval. There is some escaping done for $ and @, but not for backticks. This can be exploited for command execution if $pkt->edns->option('EXTENDED-ERROR') is called in array context, for example with a payload of {0:`"<command>"`} in EXTRA-TEXT.

CVE-2026-64194 (2026-07-20)

Net::DNS versions through 1.55 for Perl allow Denial of Service via deep DNS compression pointer chains. Net::DNS::DomainName::decode follows RFC 1035 compression pointers by recursing into itself with no depth limit. It is possible to construct a name which saturates the call stack (at least with larger TCP responses), leading to a potential Denial of Service. The guard `$link < $offset` prevents forward and circular chains, but still allows arbitrarily long backward chains. The per-offset cache (`$cache`) is populated at the start of each call and short-circuits only re-traverses of the same offset - the initial descent through a fresh chain still recurses at full depth. A crafted packet can chain two-byte compression pointers so that each one points two bytes earlier than the previous, producing a chain length of `offset / 2`. For the 14-bit pointer field (max offset 16383) this gives up to ~8191 recursive frames. For a TCP DNS message the limit is the 16-bit length field (~32767 frames). Perl's default C stack handles only a few thousand frames; beyond that the process receives SIGSEGV or similar, which is a denial-of-service for any application parsing untrusted DNS data. The vulnerability is triggered by `Net::DNS::Packet->new(\$wire)` i.e. any point where the library decodes a DNS message from the network.

NAME

Net::DNS::Resolver::Recurse - Perform recursive DNS lookups

SYNOPSIS

use Net::DNS::Resolver::Recurse;
my $res = Net::DNS::Resolver::Recurse->new;

DESCRIPTION

This module is a sub class of Net::DNS::Resolver.

METHODS

This module inherits all the methods from Net::DNS::Resolver. The additional module-specific methods are described below.

hints

Initialize the hint servers. Recursive queries need a starting name server to work from. This method takes a list of IP addresses to use as the starting servers. These name servers should be authoritative for the root (.) zone.

$res->hints(@ips);

If no hints are passed, the default nameserver is asked for the hints. Normally these IPs can be obtained from the following location:

ftp://ftp.internic.net/domain/named.root

recursion_callback

This method is takes a code reference, which is then invoked each time a packet is received during the recursive lookup. For example to emulate dig's +trace function:

$res->recursion_callback(sub {
    my $packet = shift;

    $_->print for $packet->additional;

    printf(";; Received %d bytes from %s\n\n",
        $packet->answersize,
        $packet->answerfrom
    );
});

query_dorecursion

This method is much like the normal query() method except it disables the recurse flag in the packet and explicitly performs the recursion.

$packet = $res->query_dorecursion( "www.netscape.com.", "A");

IPv6 transport

If the appropriate IPv6 libraries are installed the recursive resolver will randomly choose between IPv6 and IPv4 addresses of the nameservers it encounters during recursion.

If you want to force IPv4 transport use the force_v4() method. Also see the IPv6 transport notes in the Net::DNS::Resolver documentation.

AUTHOR

Rob Brown, bbb@cpan.org

COPYRIGHT

Copyright (c)2002, Rob Brown.

Portions Copyright (c)2005, Olaf M Kolkman.

All rights reserved.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

Net::DNS::Resolver