curl leaks file descriptors when a curl request fails or is aborted.  How to reproduce:

1. Put a file called "blah.txt" with some plain text in docroot.

2. curltest.php:

<?php
header("Content-type: text/plain");

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "http://$SERVER_NAME/blah.txt");
curl_exec($ch);
curl_close($ch);

?>

3. run httpd -X and find the process id

4. open curltest.php in your browser and hit Escape (it will hang because the Apache process is busy processing the PHP script)

5. (on Linux) ls -l /proc/<httpd-pid>/fs