Directory traversal vulnerability in the client in HexChat 2.11.0 allows remote IRC servers to read or modify arbitrary files via a .. (dot dot) in the server name.

Stack-based buffer overflow in the inbound_cap_ls function in common/inbound.c in HexChat 2.10.2 allows remote IRC servers to cause a denial of service (crash) via a large number of options in a CAP LS message.

xchat/hexchat: does not verify the server hostname matches the domain name in the subject's Common Name (CN) or subjectAltName field in X.509 certificates

The ssl_do_connect function in common/server.c in HexChat before 2.10.2, XChat, and XChat-GNOME does not verify that the server hostname matches a domain name in the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate.