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Gentoo Linux Security Advisory                           GLSA 202405-19
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                                           https://security.gentoo.org/
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 Severity: Normal
    Title: xar: Unsafe Extraction
     Date: May 07, 2024
     Bugs: #820641
       ID: 202405-19

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Synopsis
========

A vulnerability has been discovered in xar, which can lead to privilege
escalation.

Background
==========

xar provides an easily extensible archive format.

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

Package       Vulnerable           Unaffected
------------  -------------------  --------------------
app-arch/xar  < 1.8.0.0.487.100.1  >= 1.8.0.0.487.100.1

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

A vulnerability has been discovered in xar. Please review the CVE
identifier referenced below for details.

Impact
======

xar allows for a forward-slash separated path to be specified in the
file name property, e.g. <name>x/foo</name> – as long as it doesn’t
traverse upwards, and the path exists within the current directory. This
means an attacker can create a .xar file which contains both a directory
symlink, and a file with a name property which points into the extracted
symlink directory. By abusing symlink directories in this manner, an
attacker can write arbitrary files to any directory on the filesystem –
providing the user has permissions to write to it.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All xar users should upgrade to the latest version:

  # emerge --sync
  # emerge --ask --oneshot --verbose ">=app-arch/xar-1.8.0.0.487.100.1"

References
==========

[ 1 ] CVE-2021-30833
      https://nvd.nist.gov/vuln/detail/CVE-2021-30833

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

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

 https://security.gentoo.org/glsa/202405-19

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
security@gentoo.org or alternatively, you may file a bug at
https://bugs.gentoo.org.

License
=======

Copyright 2024 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