GNU Screen: User-assisted execution of arbitrary code

Background

GNU Screen is a full-screen window manager that multiplexes a physical terminal between several processes, typically interactive shells.

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"