/ 
Net-DNS-0.81
/ Net::DNS::RR::TLSA
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::RR::TLSA - DNS TLSA resource record

SYNOPSIS

use Net::DNS;
$rr = new Net::DNS::RR('name TLSA usage selector matchingtype certificate');

DESCRIPTION

The Transport Layer Security Authentication (TLSA) DNS resource record is used to associate a TLS server certificate or public key with the domain name where the record is found, forming a "TLSA certificate association". The semantics of how the TLSA RR is interpreted are described in RFC6698.

METHODS

The available methods are those inherited from the base class augmented by the type-specific methods defined in this package.

Use of undocumented package features or direct access to internal data structures is discouraged and could result in program termination or other unpredictable behaviour.

usage

$usage = $rr->usage;
$rr->usage( $usage );

8-bit integer value which specifies the provided association that will be used to match the certificate presented in the TLS handshake.

selector

$selector = $rr->selector;
$rr->selector( $selector );

8-bit integer value which specifies which part of the TLS certificate presented by the server will be matched against the association data.

matchingtype

$matchingtype = $rr->matchingtype;
$rr->matchingtype( $matchingtype );

8-bit integer value which specifies how the certificate association is presented.

cert

$cert = $rr->cert;
$rr->cert( $cert );

Hexadecimal representation of the certificate data.

certbin

$certbin = $rr->certbin;
$rr->certbin( $certbin );

Binary representation of the certificate data.

COPYRIGHT

Copyright (c)2012 Willem Toorop, NLnet Labs.

All rights reserved.

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

Package template (c)2009,2012 O.M.Kolkman and R.W.Franks.

SEE ALSO

perl, Net::DNS, Net::DNS::RR, RFC6698