[ GLSA 202105-11 ] GNU Screen

[GLSA]

Gentoo Linux Security Advisory

Title: GNU Screen: User-assisted execution of arbitrary code (GLSA 202105-11)
Severity: normal
Exploitable: local, remote
Date: 2021-05-26
Bug(s): #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: app-misc/screen
Vulnerable: < 4.8.0-r2
Unaffected: >= 4.8.0-r2
Architectures: 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: