/ 
Authen-SASL-2.1800
⭐ Starred 6 / Authen::SASL::Perl::XOAUTH2
Security Advisories (2)
CVE-2025-40918 (2025-07-16)

Authen::SASL::Perl::DIGEST_MD5 versions 2.04 through 2.1800 for Perl generates the cnonce insecurely. The cnonce (client nonce) is generated from an MD5 hash of the PID, the epoch time and the built-in rand function. The PID will come from a small set of numbers, and the epoch time may be guessed, if it is not leaked from the HTTP Date header. The built-in rand function is unsuitable for cryptographic usage. According to RFC 2831, The cnonce-value is an opaque quoted string value provided by the client and used by both client and server to avoid chosen plaintext attacks, and to provide mutual authentication. The security of the implementation depends on a good choice. It is RECOMMENDED that it contain at least 64 bits of entropy.

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::XOAUTH2 - XOAUTH2 Authentication class

VERSION

version 2.1800

SYNOPSIS

use Authen::SASL qw(Perl);

$sasl = Authen::SASL->new(
  mechanism => 'XOAUTH2',
  callback  => {
    user => $user,
    pass => $access_token
  },
);

DESCRIPTION

This module implements the client side of the XOAUTH2 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.

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.