A buffer overflow in websockets in UnrealIRCd 6.1.0 through 6.1.3 before 6.1.4 allows an unauthenticated remote attacker to crash the server by sending an oversized packet (if a websocket port is open). Remote code execution might be possible on some uncommon, older platforms.
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.