irssi - security update

An information disclosure vulnerability was found in irssi.

• CVE-2016-7553
  Other users on the same machine as the user running irssi with
  buf.pl loaded may be able to retrieve the whole window contents
  after /UPGRADE.
  Furthermore, this dump of the windows contents is never removed
  afterwards.

For Debian 7 Wheezy, this problems have been fixed in version
0.8.15-5+deb7u1.

We recommend that you upgrade your irssi packages.

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: <https://wiki.debian.org/LTS&gt;