Buffer overflow in mIRC before 6.11 allows remote attackers to execute arbitrary code via a long irc:// URL.

Buffer overflow in mIRC 6.12, when the DCC get dialog window has been minimized and the user opens the minimized window, allows remote attackers to cause a denial of service (crash) via a long filename.

mIRC before 7.55 allows remote command execution by using argument injection through custom URI protocol handlers. The attacker can specify an irc:// URI that loads an arbitrary .ini file from a UNC share pathname. Exploitation depends on browser-specific URI handling (Chrome is not exploitable).