Heap-based buffer overflow in Xchat-WDK before 1499-4 (2012-01-18) xchat 2.8.6 on Maemo architecture could allow remote attackers to cause a denial of service (xchat client crash) or execute arbitrary code via a UTF-8 line from server containing characters outside of the Basic Multilingual Plane (BMP).

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.

Heap-based buffer overflow in XChat 2.8.9 and earlier allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a long response string.

Untrusted search path vulnerability in the Python module in xchat allows local users to execute arbitrary code via a Trojan horse Python file in the current working directory, related to a vulnerability in the PySys_SetArgv function (CVE-2008-5983).

Argument injection vulnerability in XChat 2.8.7b and earlier on Windows, when Internet Explorer is used, allows remote attackers to execute arbitrary commands via the --command parameter in an ircs:// URI.

Unspecified vulnerability in Xchat 2.6.7 and earlier allows remote attackers to cause a denial of service (crash) via unspecified vectors involving the PRIVMSG command. NOTE: the vendor has disputed this vulnerability, stating that it does not affect 2.6.7 "or any recent version"

Stack-based buffer overflow in the Socks-5 proxy code for XChat 1.8.0 to 2.0.8, with socks5 traversal enabled, allows remote attackers to execute arbitrary code.

xchat 2.0.6 allows remote attackers to cause a denial of service (crash) via a passive DCC request with an invalid ID number, which causes a null dereference.

XChat 1.8.7 and earlier, including default configurations of 1.4.2 and 1.4.3, allows remote attackers to execute arbitrary IRC commands as other clients via encoded characters in a PRIVMSG command that calls CTCP PING, which expands the characters in the client response when the percascii variable is set.

XChat IRC client allows remote attackers to execute arbitrary commands via a /dns command on a host whose DNS reverse lookup contains shell metacharacters.

Format string vulnerability in XChat 1.2.x allows remote attackers to execute arbitrary code via a malformed nickname.

IRC Xchat client versions 1.4.2 and earlier allows remote attackers to execute arbitrary commands by encoding shell metacharacters into a URL which XChat uses to launch a web browser.