A buffer overflow has been discovered in the Socks-5 proxy code of XChat, an IRC client for X similar to AmIRC. This allows an attacker to execute arbitrary code on the users' machine.
For the stable distribution (woody) this problem has been fixed in version 1.8.9-0woody3.
For the unstable distribution (sid) this problem has been fixed in version 2.0.8-1.
We recommend that you upgrade your xchat and related packages.