The Jargon File (version 4.4.7, 29 Dec 2003):

firehose syndrome
 n.

    In mainstream folklore it is observed that trying to drink from a firehose
    can be a good way to rip your lips off. On computer networks, the absence
    or failure of flow control mechanisms can lead to situations in which the
    sending system sprays a massive flood of packets at an unfortunate
    receiving system, more than it can handle. Compare overrun, buffer
    overflow.


The Free On-line Dictionary of Computing (30 December 2018):

firehose syndrome

    An absence, failure or inadequacy of flow
   control mechanisms causing the sender to overwhelm the
   receiver.  The implication is that, like trying to drink from
   a firehose, the consequenses are worse than just loss of data,
   e.g. the receiver may crash.

   See ping-flood.

   [Jargon File]

   (2007-03-12)