smtp.c in the c-client library in University of Washington IMAP Toolkit 2007b allows remote SMTP servers to cause a denial of service (NULL pointer dereference…

smtp.c in the c-client library in University of Washington IMAP Toolkit 2007b allows remote SMTP servers to cause a denial of service (NULL pointer dereference and application crash) by responding to the QUIT command with a close of the TCP connection instead of the expected 221 response code.