F21 JWT fails to verify token signatures


JWT provided by F21 is a PHP library for handling JSON Web Tokens. php-jwt contains a vulnerability where it fails to verify token signatures.

Toshiharu Sugiyama of DeNA Co., Ltd. and Shuntaro Maeda 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: Partial
  • Availability Impact: None
Affected Products

  • JWT versions prior to 2.0


Specially crafted tokens may be validated as token data with valid signatures.

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

CWE (What is CWE?)

  1. No Mapping(CWE-Other) [IPA Evaluation]
CVE (What is CVE?)

  1. CVE-2015-2951

  1. JVN : JVN#06120222
  2. National Vulnerability Database (NVD) : CVE-2015-2951
Revision History

  • [2015/06/03]
      Web page was published
      References : Content was added