Published:2015/06/25  Last Updated:2015/06/25

namshi/jose fails to verify token signatures


namshi/jose contains a vulnerability where it fails to verify token signatures.

Products Affected

  • namshi/jose 2.2.1 and earlier
  • namshi/jose 3.0.0 and earlier
  • namshi/jose 4.0.0 and earlier
  • namshi/jose 5.0.0 and earlier


namshi/jose is a PHP library for handling JSON Web Tokens (JWT). namshi/jose contains a vulnerability in processing JWT headers where it fails to verify token signatures.


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


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

Vendor Status

Vendor Link
Namshi namshi/jose


JPCERT/CC Addendum

Vulnerability Analysis by JPCERT/CC

Analyzed on 2015.06.25 (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 no impact to the confidentiality of the system.
Integrity Impact(I) None (N) Partial (P) Complete (C) Modification of some system files or information is possible, but the attacker does not have control over what can be modified, or the scope of what the attacker can affect is limited.
Availability Impact(A) None (N) Partial (P) Complete (C) There is no impact to the availability of the system.

Base Score:5.0


Toshiharu Sugiyama of DeNA Co., Ltd. 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-2015-2964
JVN iPedia JVNDB-2015-000090