/ 
Net-DNS-1.55_01
/ Net::DNS::Mailbox
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::Mailbox - DNS mailbox representation

SYNOPSIS

use Net::DNS::Mailbox;

$mailbox = Net::DNS::Mailbox->new('user@example.com');
$address = $mailbox->address;

DESCRIPTION

The Net::DNS::Mailbox module implements a subclass of DNS domain name objects representing the DNS coded form of RFC822 mailbox address.

The Net::DNS::Mailbox1035 and Net::DNS::Mailbox2535 packages implement mailbox representation subtypes which provide the name compression and canonicalisation specified by RFC1035 and RFC2535. These are necessary to meet the backward compatibility requirements introduced by RFC3597.

METHODS

new

$mailbox = Net::DNS::Mailbox->new('John Doe <john.doe@example.com>');
$mailbox = Net::DNS::Mailbox->new('john.doe@example.com');
$mailbox = Net::DNS::Mailbox->new('john\.doe.example.com');

Creates a mailbox object representing the RFC822 mail address specified by the character string argument. An encoded domain name is also accepted for backward compatibility with Net::DNS 0.68 and earlier.

The argument string consists of printable characters from the 7-bit ASCII repertoire.

address

$address = $mailbox->address;

Returns a character string containing the RFC822 mailbox address corresponding to the encoded domain name representation described in RFC1035 section 8.

COPYRIGHT

Copyright (c)2009,2012 Dick Franks.

All rights reserved.

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::DomainName RFC1035 RFC5322