/ 
Net-DNS-1.55_01
/ Net::DNS::RR::DELEG
Security Advisories (1)
CVE-2026-81928 (2026-09-01)

Net::DNS versions before 1.57 for Perl allow memory exhaustion via unbounded recursion in sig_data when re-encoding a message with a misplaced TSIG record. sig_data signs a message by re-encoding it, and removes TSIG records only from the additional section. A TSIG decoded into the answer or authority section survives that step and is signed again, so encoding re-enters sig_data with no termination condition. Decoding does not reject such a message: a TSIG that is not the last record on the wire raises "misplaced or corrupt TSIG", but the error is caught, reported as a warning, and the record is left in the packet. RFC 8945 section 5.2 requires the message to be dropped. The recursion is reached only when the decoded TSIG carries an empty MAC, since a MAC recovered from the wire short-circuits the signing step. It is reached only from code that re-encodes a message it decoded, such as a forwarder or a proxy. A decoded message that is never re-encoded is unaffected. Message direction does not matter: a query reaches the same path as a response. Each cycle re-encodes the whole message, so fewer than 100 bytes on the wire exhaust available memory and terminate the process.

NAME

Net::DNS::RR::DELEG - DNS DELEG resource record

SYNOPSIS

use Net::DNS;
$rr = Net::DNS::RR->new('zone DELEG server-ipv4=192.0.2.1 ...');
$rr = Net::DNS::RR->new('zone DELEG server-ipv6=2001:db8::53 ...');
$rr = Net::DNS::RR->new('zone DELEG server-name=nameserver.example ...');
$rr = Net::DNS::RR->new('zone DELEG include-delegparam=provider.example');

DESCRIPTION

The DNS DELEG resource record set, wherever it appears, designates the authoritative nameservers and transport parameters to be used to resolve queries for data at the owner name or any subordinate thereof.

The DELEG RRset is authoritative data within the delegating zone. A DELEG RRset must not appear at the apex of a delegated zone.

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.

server_ipv4

eg.example. DELEG server-ipv4=192.0.2.1,...
@ip = $rr->server_ipv4;

Sets or gets a list of IP addresses.

server_ipv6

eg.example. DELEG server-ipv6=2001:db8::53,...
@ip = $rr->server_ipv6;

Sets or gets a list of IP addresses.

server_name

eg.example. DELEG server-name=nameserver.example.
$nameserver = $rr->server_name;

Specifies the domain name of the nameserver.

Returns the nameserver domain name or the undefined value if not specified.

include_delegparam

eg.example. DELEG include-delegparam=provider.example.
$destination = $rr->include_delegparam;

Specifies the location of a devolved nameserver configuration.

Returns the destination domain name or the undefined value if not specified.

COPYRIGHT

Copyright (c)2025-2026 Dick Franks.

All rights reserved.

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

LICENSE

Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the original copyright notices appear in all copies and that both copyright notice and this permission notice appear in supporting documentation, and that the name of the author not be used in advertising or publicity pertaining to distribution of the software without specific prior written permission.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

SEE ALSO

perl Net::DNS Net::DNS::RR draft-ietf-deleg-10