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Net-BitTorrent-v2.1.0
⭐ Starred 13 / Net::BitTorrent::Protocol::Simulation
Security Advisories (2)
CVE-2026-57080 (2026-06-30)

Net::BitTorrent versions through 2.1.0 for Perl allow remote memory exhaustion via an uncapped peer-wire message-length prefix. The peer-wire framing in _process_messages trusts the 4-byte length prefix sent by a connected peer with no upper bound, while receive_data appends every inbound byte to the input buffer. A peer announces a length prefix of up to about 4 GiB and then streams bytes; the decoder waits until the buffer holds the full message before processing it, so the buffer grows without limit. Peer connections are unauthenticated, so any peer in the swarm exhausts the downloading process's memory. The largest legitimate message is a 16 KiB piece block, so any announced length far above that is anomalous.

CVE-2026-57081 (2026-06-30)

Net::BitTorrent versions through 2.1.0 for Perl allow remote memory exhaustion via deeply nested bencoded input. bdecode recurses once per nested list or dictionary level with no depth cap, and each recursive call receives the remaining buffer by value while the list and dictionary branches capture the whole remainder, so every live recursion frame keeps its own copy of the shrinking buffer (O(N^2) bytes for an N-deep input). The decoder runs on every untrusted bencode source: .torrent files, BEP09 metadata fetched from peers, DHT messages, and tracker responses. A bencoded input of roughly 150,000 nested lists (about 150 KB on the wire) drives multi-gigabyte peak memory, so one short message from any peer, or one crafted .torrent file or magnet link, terminates the client.

NAME

Net::BitTorrent::Protocol::Simulation - Protocol handler for tests and swarm simulations

SYNOPSIS

use Net::BitTorrent::Protocol::Simulation;

my $proto = Net::BitTorrent::Protocol::Simulation->new(
    peer_id  => $my_id,
    infohash => $ih
);
$proto->peer($peer_object);

DESCRIPTION

Net::BitTorrent::Protocol::Simulation is a subclass of Net::BitTorrent::Protocol::BEP11 designed for use in tests and simulations.

It allows a Net::BitTorrent::Peer object to be associated directly with the protocol handler, bypassing the usual event-driven network transport for easier manipulation of peer state during simulated swarm behavior.

METHODS

peer( )

Returns or sets the associated Peer object.

my $p = $proto->peer();
$proto->peer( $p );

Expected parameters:

$peer - optional

The Peer object to associate with this handler.

_handle_message( $id, $payload )

Internal method that overrides the default message handling to forward messages to the associated peer object before passing them up the inheritance chain.

SEE ALSO

Net::BitTorrent::Protocol::BEP11, Net::BitTorrent::Peer

AUTHOR

Sanko Robinson - https://github.com/sanko

COPYRIGHT

Copyright (C) 2008-2026 by Sanko Robinson.

This library is free software; you can redistribute it and/or modify it under the terms of the Artistic License 2.0.