lighttpd before 1.4.20 compares URIs to patterns in the (1) url.redirect and (2) url.rewrite configuration settings before performing URL decoding, which might allow remote attackers to bypass intended access restrictions, and obtain sensitive information or possibly modify data.
mod_userdir in lighttpd before 1.4.20, when a case-insensitive operating system or filesystem is used, performs case-sensitive comparisons on filename components in configuration options, which might allow remote attackers to bypass intended access restrictions, as demonstrated by a request for a .PHP file when there is a configuration rule for .php files.
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.
The connection_state_machine function (connections.c) in lighttpd 1.4.19 and earlier, and 1.5.x before 1.5.0, allows remote attackers to cause a denial of service (active SSL connection loss) by triggering an SSL error, such as disconnecting before a download has finished, which causes all active SSL connections to be lost.