haproxy: http_get_hdr()/get_ip_from_hdr2() MAX_HDR_HISTORY handling denial of service

HAProxy 1.4 before 1.4.24 and 1.5 before 1.5-dev19, when configured to use hdrip or other "hdr" functions with a negative occurrence count, allows remote attackers to cause a denial of service negative array index usage and crash via an HTTP header with a certain number of values, related to the...