xterm: Arbitrary Code Execution

Background

xterm is a terminal emulator for the X Window system.

Description

xterm does not correctly handle control characters related to OSC 50 font ops sequence handling.

Impact

The vulnerability allows text written to the terminal to write text to the terminal’s command line. If the terminal’s shell is zsh running with vi line editing mode, text written to the terminal can also trigger the execution of arbitrary commands via writing ^G to the terminal.

Workaround

As a workaround, users can disable xterm’s usage of OSC 50 sequences by adding the following to the XResources configuration: XTerm*allowFontOps: false

Resolution

All xterm users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=x11-terms/xterm-375"