GLSA 202105-11: GNU Screen: User-assisted execution of arbitrary code

http://security.gentoo.org/

Severity:	normal
Title:	GNU Screen: User-assisted execution of arbitrary code
Date:	05/26/2021
Bugs:	#769770
ID:	202105-11

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	Architecture(s)
app-misc/screen	< 4.8.0-r2	>= 4.8.0-r2	All supported architectures

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

CVE-2021-26937

Availability

This GLSA and any updates to it are available for viewing at the Gentoo Security Website: http://security.gentoo.org/glsa/glsa-202105-11.xml

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.