HydraIRC 0.3.164 and earlier allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a long irc:// URI.
Format string vulnerability in HydraIRC 0.3.151 allows remote attackers to cause a denial of service via format string specifiers in certain data related to failed DCC file transfer negotiation.
Heap-based buffer overflow in HydraIRC 0.3.151 allows remote IRC servers to cause a denial of service (application crash) via a long CTCP request message containing '%' (percent) characters.