The configuration file for the FastCGI PHP support for lighttpd before 1.4.28 on Debian GNU/Linux creates a socket file with a predictable name in /tmp, which allows local users to hijack the PHP control socket and perform unauthorized actions such as forcing the use of a different version of PHP via a symlink attack or a race condition.
https://exchange.xforce.ibmcloud.com/vulnerabilities/82897
http://www.securityfocus.com/bid/58528