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Gentoo Linux Security Advisory GLSA 202105-11
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https://security.gentoo.org/
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Severity: Normal
Title: GNU Screen: User-assisted execution of arbitrary code
Date: May 26, 2021
Bugs: #769770
ID: 202105-11
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Synopsis
========
A vulnerability in GNU screen may allow a remote attacker to execute
arbitrary code.
Background
==========
GNU Screen is a full-screen window manager that multiplexes a physical
terminal between several processes, typically interactive shells.
Affected packages
=================
-------------------------------------------------------------------
Package / Vulnerable / Unaffected
-------------------------------------------------------------------
1 app-misc/screen < 4.8.0-r2 >= 4.8.0-r2
Description
===========
It was discovered that GNU screen did not properly handle certain UTF-8
character sequences.
Impact
======
A remote attacker could entice a user to run a program where attacker
controls the output inside a GNU screen session, possibly resulting in
execution of arbitrary code with the privileges of the process or a
Denial of Service condition.
Workaround
==========
This vulnerability can be mitigated by disabling UTF-8 processing in
.screenrc.
Resolution
==========
All GNU screen users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-misc/screen-4.8.0-r2"
References
==========
[ 1 ] CVE-2021-26937
https://nvd.nist.gov/vuln/detail/CVE-2021-26937
Availability
============
This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:
https://security.gentoo.org/glsa/202105-11
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
secur...@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
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