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.

lighttpd before 1.4.26, and 1.5.x, allocates a buffer for each read operation that occurs for a request, which allows remote attackers to cause a denial of service (memory consumption) by breaking a request into small pieces that are sent at a slow rate.

Memory leak in the http_request_parse function in request.c in lighttpd before 1.4.20 allows remote attackers to cause a denial of service (memory consumption) via a large number of requests with duplicate request headers.

lighttpd 1.4.18, and possibly other versions before 1.5.0, does not properly calculate the size of a file descriptor array, which allows remote attackers to cause a denial of service (crash) via a large number of connections, which triggers an out-of-bounds access.