<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE glsa SYSTEM "http://www.gentoo.org/dtd/glsa.dtd">
<glsa id="202105-11">
  <title>GNU Screen: User-assisted execution of arbitrary code</title>
  <synopsis>A vulnerability in GNU screen may allow a remote attacker to
    execute arbitrary code.
  </synopsis>
  <product type="ebuild">screen</product>
  <announced>2021-05-26</announced>
  <revised count="1">2021-05-26</revised>
  <bug>769770</bug>
  <access>local, remote</access>
  <affected>
    <package name="app-misc/screen" auto="yes" arch="*">
      <unaffected range="ge">4.8.0-r2</unaffected>
      <vulnerable range="lt">4.8.0-r2</vulnerable>
    </package>
  </affected>
  <background>
    <p>GNU Screen is a full-screen window manager that multiplexes a physical
      terminal between several processes, typically interactive shells.
    </p>
  </background>
  <description>
    <p>It was discovered that GNU screen did not properly handle certain UTF-8
      character sequences.
    </p>
  </description>
  <impact type="normal">
    <p>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.
    </p>
  </impact>
  <workaround>
    <p>This vulnerability can be mitigated by disabling UTF-8 processing in
      .screenrc.
    </p>
  </workaround>
  <resolution>
    <p>All GNU screen users should upgrade to the latest version:</p>
    
    <code>
      # emerge --sync
      # emerge --ask --oneshot --verbose "&gt;=app-misc/screen-4.8.0-r2"
    </code>
    
  </resolution>
  <references>
    <uri link="https://nvd.nist.gov/vuln/detail/CVE-2021-26937">CVE-2021-26937</uri>
  </references>
  <metadata tag="requester" timestamp="2021-05-25T21:07:51Z">whissi</metadata>
  <metadata tag="submitter" timestamp="2021-05-26T08:14:58Z">whissi</metadata>
</glsa>
