==========================================================================
Ubuntu Security Notice USN-3527-1
January 10, 2018

irssi vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 17.10
- Ubuntu 17.04
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

Several security issues were fixed in Irssi.

Software Description:
- irssi: terminal based IRC client

Details:

Joseph Bisch discovered that Irssi incorrectly handled incomplete escape
codes. If a user were tricked into using malformed commands or opening
malformed files, an attacker could use this issue to cause Irssi to crash,
resulting in a denial of service. (CVE-2018-5205)

Joseph Bisch discovered that Irssi incorrectly handled settings the channel
topic without specifying a sender. A malicious IRC server could use this
issue to cause Irssi to crash, resulting in a denial of service.
(CVE-2018-5206)

Joseph Bisch discovered that Irssi incorrectly handled incomplete variable
arguments. If a user were tricked into using malformed commands or opening
malformed files, an attacker could use this issue to cause Irssi to crash,
resulting in a denial of service. (CVE-2018-5207)

Joseph Bisch discovered that Irssi incorrectly handled completing certain
strings. An attacker could use this issue to cause Irssi to crash,
resulting in a denial of service, or possibly execute arbitrary code.
(CVE-2018-5208)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 17.10:
  irssi                           1.0.4-1ubuntu2.2

Ubuntu 17.04:
  irssi                           0.8.20-2ubuntu2.3

Ubuntu 16.04 LTS:
  irssi                           0.8.19-1ubuntu1.6

Ubuntu 14.04 LTS:
  irssi                           0.8.15-5ubuntu3.4

After a standard system update you need to restart Irssi to make all the
necessary changes.

References:
  https://www.ubuntu.com/usn/usn-3527-1
  CVE-2018-5205, CVE-2018-5206, CVE-2018-5207, CVE-2018-5208

Package Information:
  https://launchpad.net/ubuntu/+source/irssi/1.0.4-1ubuntu2.2
  https://launchpad.net/ubuntu/+source/irssi/0.8.20-2ubuntu2.3
  https://launchpad.net/ubuntu/+source/irssi/0.8.19-1ubuntu1.6
  https://launchpad.net/ubuntu/+source/irssi/0.8.15-5ubuntu3.4