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Authen-SASL-2.2000
⭐ Starred 6 / Authen::SASL::Perl::OAUTHBEARER
Security Advisories (1)
CVE-2026-86219 (2026-09-06)

Authen::SASL::Perl::DIGEST_MD5 versions before 2.2100 for Perl accept replayed authentication responses via unverified nonce in server_step. server_start generates a fresh nonce and sends it in the challenge, and nothing later compares that value against the nonce the client returns. server_step derives the expected digest from the client's own parameters, so a response verifies whenever its digest matches the nonce it carries. The count table it also checks is keyed on the client-supplied nonce and starts empty in each new server object, so a captured first response, carrying `nc=00000001`, passes that too. RFC 2831 defines the nonce in the response as the value the server sent in the preceding challenge. An attacker who observes one successful `qop=auth` exchange can replay the captured response against a later session for the same service, host, realm and user, and authenticate as that user without knowing the password.

NAME

Authen::SASL::Perl::OAUTHBEARER - OAUTHBEARER Authentication class

VERSION

version 2.2000

SYNOPSIS

use Authen::SASL qw(Perl);

$sasl = Authen::SASL->new(
  mechanism => 'OAUTHBEARER',
  callback  => {
    user => $user,
    host => $hostname, #optional
    port => $port, #optional
    pass => $access_token
  },
);

DESCRIPTION

This module implements the client side of the OAUTHBEARER SASL mechanism, which is used for OAuth 2.0-based authentication.

CALLBACK

The callbacks used are:

Client

user

The username to be used for authentication.

host

The hostname to which the client will connect to. It is optional and can be omitted.

port

The destination port that the client will connect to. It should be a decimal positive integer string without leading zeros. It is optional and can be omitted.

pass

The OAuth 2.0 access token to be used for authentication.

SEE ALSO

Authen::SASL, Authen::SASL::Perl

AUTHORS

Written by Aditya Garg and Julian Swagemakers.

COPYRIGHT

Copyright (c) 2025 Aditya Garg.

Copyright (c) 2025 Julian Swagemakers.

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