See: http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0458
irssi 0.8.10 final version is not affected.
I see that 0.8.10 is in EPEL-5, but 0.8.9 is in EPEL-4. Could you push a 0.8.10 version to EL-4 and/or backport a patch?