An issue was discovered in Irssi before 1.0.7 and 1.1.x before 1.1.1. There is a use-after-free when a server is disconnected during netsplits. NOTE: this issue exists because of an incomplete fix for CVE-2017-7191.
https://www.debian.org/security/2018/dsa-4162
https://usn.ubuntu.com/4046-1/
https://usn.ubuntu.com/3590-1/