Embedthis Appweb before 4.6.6 and 5.x before 5.2.1 allows remote attackers to cause a denial of service (NULL pointer dereference) via a Range header with an empty value, as demonstrated by "Range: x=,".
http://packetstormsecurity.com/files/131157/Appweb-Web-Server-Denial-Of-Service.html
http://seclists.org/fulldisclosure/2015/Apr/19
http://seclists.org/fulldisclosure/2015/Mar/158
https://security.paloaltonetworks.com/CVE-2014-9708
http://www.openwall.com/lists/oss-security/2015/03/28/2
http://www.openwall.com/lists/oss-security/2015/04/06/2
http://www.oracle.com/technetwork/security-advisory/cpujul2016-2881720.html