IRSSI-SA-2018-01 Irssi Security Advisory [1]
============================================
CVE-2018-5206, CVE-2018-5205, CVE-2018-5208, CVE-2018-5207

Description
-----------

Multiple vulnerabilities have been located in Irssi.

(a) When the channel topic is set without specifying a sender, Irssi
    may dereference NULL pointer. Found by Joseph Bisch. (CWE-476)

    CVE-2018-5206 was assigned to this issue.

(b) When using incomplete escape codes, Irssi may access data beyond
    the end of the string. (CWE-126) Found by Joseph Bisch.

    CVE-2018-5205 was assigned to this issue.

(c) A calculation error in the completion code could cause a heap
    buffer overflow when completing certain strings. (CWE-126) Found
    by Joseph Bisch.

    CVE-2018-5208 was assigned to this issue.

(d) When using an incomplete variable argument, Irssi may access data
    beyond the end of the string. (CWE-126) Found by Joseph Bisch.

    CVE-2018-5207 was assigned to this issue.


Impact
------

May affect the stability of Irssi.


Affected versions
-----------------

(a,b,c,d) All Irssi versions that we observed.


Fixed in
--------

Irssi 1.0.6


Recommended action
------------------

Upgrade to Irssi 1.0.6. Irssi 1.0.6 is a maintenance release in the
1.0 series, without any new features.

After installing the updated packages, one can issue the /upgrade
command to load the new binary. TLS connections will require
/reconnect.


Mitigating facts
----------------

(a) requires a broken ircd or control over the ircd

(b,d) requires user to install malicious or broken files or enter
      affected commands


Patch
-----
https://github.com/irssi/irssi/releases/download/1.0.6/irssi-1.0.5_1.0.6.diff


References
----------

[1] https://irssi.org/security/irssi_sa_2018_01.txt