[ GLSA 202601-01 ] inetutils: Remote Code Execution

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Gentoo Linux Security Advisory                           GLSA 202601-01
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                                           https://security.gentoo.org/
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 Severity: High
    Title: inetutils: Remote Code Execution
     Date: January 26, 2026
     Bugs: #969065
       ID: 202601-01

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Synopsis
========

A vulnerability has been discovered in the telnetd module of inetutils,
which allows remote code execution as root.

Background
==========

Inetutils is a collection of common network programs including a telnet
client and server.

Affected packages
=================

Package             Vulnerable    Unaffected
------------------  ------------  ------------
net-misc/inetutils  < 2.7         >= 2.7

Description
===========

The telnetd server invokes /usr/bin/login (normally running as root)
passing the value of the USER environment variable received from the
client as the last parameter.

If the client supply a carefully crafted USER environment value being
the string "-f root", and passes the telnet(1) -a or --login parameter
to send this USER environment to the server, the client will be
automatically logged in as root bypassing normal authentication
processes.

This happens because the telnetd server do not sanitize the USER
environment variable before passing it on to login(1), and login(1) uses
the -f parameter to by-pass normal authentication.

Impact
======

An attacker can login as root via the telnetd daemon.

Workaround
==========

Reinstall inetutils with the telnetd USE flag disabled. This is the
default in Gentoo.

Resolution
==========

All inetutils users with the telnetd USE flag enabled should upgrade to
the latest version:

  # emerge --sync
  # emerge --ask --oneshot --verbose ">=net-misc/inetutils-2.7"

References
==========

[ 1 ] CVE-2026-24061
      https://nvd.nist.gov/vuln/detail/CVE-2026-24061

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

 https://security.gentoo.org/glsa/202601-01

Concerns?
=========

Security is a primary focus of Gentoo Linux and ensuring the
confidentiality and security of our users' machines is of utmost
importance to us. Any security concerns should be addressed to
[email protected] or alternatively, you may file a bug at
https://bugs.gentoo.org.

License
=======

Copyright 2026 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).

The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.

https://creativecommons.org/licenses/by-sa/2.5
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