H2O vulnerable to directory traversal


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.

Yusuke OSUMI reported this vulnerability to IPA.
JPCERT/CC coordinated with the developer under Information Security Early Warning Partnership.
CVSS Severity (What is CVSS?)

CVSS V2 Severity:
Base Metrics 5.0 (Medium) [IPA Score]
  • Access Vector: Network
  • Access Complexity: Low
  • Authentication: None
  • Confidentiality Impact: Partial
  • Integrity Impact: None
  • Availability Impact: None
Affected Products

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


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

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Update to the latest version according to the information provided by the developer.
Vendor Information

Kazuho Oku
CWE (What is CWE?)

  1. Path Traversal(CWE-22) [IPA Evaluation]
CVE (What is CVE?)

  1. CVE-2015-5638

  1. JVN : JVN#65602714
  2. National Vulnerability Database (NVD) : CVE-2015-5638
Revision History

  • [2015/09/17]
      Web page was published
      References : Content was added