Directory traversal vulnerability in H2O before 1.4.5 and 1.5.x before 1.5.0-beta2, when the file.dir directive is enabled, allows remote attackers to read arbitrary files via a crafted URL.
https://h2o.examp1e.net/vulnerabilities.html#CVE-2015-5638
https://euvd.enisa.europa.eu/vulnerability/EUVD-2015-5590