A stunnel security update has been released for Gentoo Linux.

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Gentoo Linux Security Advisory GLSA 202105-02
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  https://security.gentoo.org/
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Severity: Low
Title: stunnel: Improper certificate validation
Date: May 26, 2021
Bugs: #772146
ID: 202105-02

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Synopsis
========

Stunnel was not properly verifying TLS certificates, possibly allowing
an integrity/confidentiality compromise.

Background
==========

The stunnel program is designed to work as an SSL/TLS encryption
wrapper between a client and a local or remote server.

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

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Package / Vulnerable / Unaffected
-------------------------------------------------------------------
1 net-misc/stunnel < 5.58 >= 5.58

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

It was discovered that stunnel did not correctly verified the client
certificate when options "redirect" and "verifyChain" are used.

Impact
======

A remote attacker could send a specially crafted certificate, possibly
resulting in a breach of integrity or confidentiality.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All stunnel users should upgrade to the latest version:

# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/stunnel-5.58"

References
==========

[ 1 ] CVE-2021-20230
  https://nvd.nist.gov/vuln/detail/CVE-2021-20230

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

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

  https://security.gentoo.org/glsa/202105-02

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 2021 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