Published:2015/09/17  Last Updated:2015/09/17

H2O vulnerable to directory traversal


H2O contains a directory traversal vulnerability.

Products Affected

  • H2O version 1.4.4 and earlier
  • H2O version 1.5.0-beta1 and earlier


H2O is an open source web server software. H2O contains an issue in processing URL, which may result in a directory traversal (CWE-22) vulnerability.


A remote attacker may obtain arbitrary files on the server if "file.dir" directive is specified.


Update the Software
Update to the latest version according to the information provided by the developer.

Vendor Status

Vendor Status Last Update Vendor Notes
Kazuho Oku Vulnerable 2015/09/17 Kazuho Oku website


JPCERT/CC Addendum

Vulnerability Analysis by JPCERT/CC

Analyzed on 2015.09.17 (CVSS Base Metrics)

What is CVSS?

Measures Severity Description
Access Vector(AV) Local (L) Adjacent Network (A) Network (N) A vulnerability exploitable with network access means the vulnerable software is bound to the network stack and the attacker does not require local network access or local access. Such a vulnerability is often termed "remotely exploitable".
Access Complexity(AC) High (H) Medium (M) Low (L) Specialized access conditions or extenuating circumstances do not exist.
Authentication(Au) Multiple (M) Single (S) None (N) Authentication is not required to exploit the vulnerability.
Confidentiality Impact(C) None (N) Partial (P) Complete (C) There is considerable informational disclosure. Access to some system files is possible, but the attacker does not have control over what is obtained, or the scope of the loss is constrained.
Integrity Impact(I) None (N) Partial (P) Complete (C) There is no impact to the integrity of the system.
Availability Impact(A) None (N) Partial (P) Complete (C) There is no impact to the availability of the system.

Base Score:5.0


Yusuke OSUMI reported this vulnerability to IPA.
JPCERT/CC coordinated with the developer under Information Security Early Warning Partnership.

Other Information

JPCERT Reports
CERT Advisory
CPNI Advisory
CVE CVE-2015-5638
JVN iPedia JVNDB-2015-0000136