IRSSI-SA-2017-03 Irssi Security Advisory 
use after free condition during netjoin processing
Use after free while producing list of netjoins (CWE-416)
This issue was found and reported to us by APic.
See CVE-2018-7054 for an update regarding this issue, this fix was incomplete.
CVE-2017-7191  was assigned to this issue.
This issue usually leads to segmentation faults. Targeted code execution should be difficult.
Irssi 1.0.0 and later
We believe Irssi 0.8.21 and prior are not affected since a different code path causes the netjoins to be flushed prior to reaching the use after free condition.
Irssi 1.0.7, 1.1.1
Upgrade to Irssi 1.0.2. Irssi 1.0.2 is a maintenance release without any new features.