Ruby hash table implementation vulnerable to denial-of-service


The hash table implementation in Ruby contains a denial-of-service (DoS) vulnerability.

The hash table implementation in Ruby contains an issue, where it may intentionally create a series of strings whose hash values collide. As a result, a denial-of-service (DoS) attack may be conducted.

Tanaka Akira of National Institute of Advanced Industrial Science and Technology (AIST) 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: None
  • Integrity Impact: None
  • Availability Impact: Partial
Affected Products

  • Ruby versions prior to 1.8.7-p357
  • Ruby 1.9.x versions prior to 1.9.1


When processing a series of specially crafted strings, a denial-of-service (DoS) may occur.

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

Ruby Apple Inc.
  • Apple Security Updates : HT5281
Oracle Corporation
CWE (What is CWE?)

  1. Resource Management Errors(CWE-399) [IPA Evaluation]
CVE (What is CVE?)

  1. CVE-2011-4815

  1. JVN : JVN#90615481
  2. JVN : JVNVU#692779 (Japanese only)
  3. National Vulnerability Database (NVD) : CVE-2011-4815
  4. IPA SECURITY ALERTS : 20120106-web (Japanese only)
  5. US-CERT Vulnerability Note : VU#903934
Revision History

  • [2012/07/06]
      Web page was published