CRLF injection vulnerability in the on_req function in lib/handler/redirect.c in H2O before 1.6.2 and 1.7.x before 1.7.0-beta3 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via a crafted URI.
https://h2o.examp1e.net/vulnerabilities.html#CVE-2016-1133
https://github.com/h2o/h2o/issues/684
https://github.com/h2o/h2o/issues/682