This indicates an attack attempt to exploit a Denial of Service Vulnerability in Lighttpd Project Lighttpd.
A remote, unauthenticated attacker can exploit this vulnerability by sending a maliciously crafted HTTP request to the target server. Successful exploitation of this vulnerability could result in denial-of-service conditions on the target server.
Lighttpd Project Lighttpd prior to 1.4.54
Denial of Service: Remote attackers can crash vulnerable systems.
Apply the most recent upgrade or patch from the vendor.