The net/http library in net/http/transfer.go in Go before 1.4.3 does not properly parse HTTP headers, which allows remote attackers to conduct HTTP request smuggling attacks via a request with two Content-length headers.
https://github.com/golang/go/commit/300d9a21583e7cf0149a778a0611e76ff7c6680f
https://bugzilla.redhat.com/show_bug.cgi?id=1250352
http://seclists.org/oss-sec/2015/q3/294
http://seclists.org/oss-sec/2015/q3/292
http://seclists.org/oss-sec/2015/q3/237
http://rhn.redhat.com/errata/RHSA-2016-1538.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-October/168029.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-October/167997.html