psyBNC 2.3 beta and earlier allows remote attackers to spoof encrypted, trusted messages by sending lines that begin with the "[B]" sequence, which makes the message appear legitimate.

psyBNC 2.3 allows remote attackers to cause a denial of service (CPU consumption and resource exhaustion) by sending a PASS command with a long password argument and quickly killing the connection, which is not properly terminated by psyBNC.