Gurunavi Apps fail to restrict access permissions


Gurunavi Apps provided by Gurunavi, Inc. implement the function to access a requested URL using Custom URL Scheme.
This function contains an improper access control vulnerability (CWE-284) that may allow the vulnerable App to receive an request from an arbitrary App and execute an access.

Ryo Sato of BroadBand Security,Inc. reported this vulnerability to IPA.
JPCERT/CC coordinated with the developer under Information Security Early Warning Partnership.
CVSS Severity (What is CVSS?)

CVSS V3 Severity:
Base Metrics 3.3 (Low) [IPA Score]
  • Attack Vector: Local
  • Attack Complexity: Low
  • Privileges Required: None
  • User Interaction: Required
  • Scope: Unchanged
  • Confidentiality Impact: None
  • Integrity Impact: Low
  • Availability Impact: None
CVSS V2 Severity:
Base Metrics 4.3 (Medium) [IPA Score]
  • Access Vector: Network
  • Access Complexity: Medium
  • Authentication: None
  • Confidentiality Impact: None
  • Integrity Impact: Partial
  • Availability Impact: None
Affected Products

Gurunavi, Inc.
  • Gurunavi App for Android ver.10.0.14 and earlier
  • Gurunavi App for iOS ver.11.2.3 and earlier


A remote attacker may lead a user to access an arbitrary website via the vulnerable App. As a result, the user may become a victim of a phishing attack.

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

Gurunavi, Inc.
CWE (What is CWE?)

  1. Permissions(CWE-264) [IPA Evaluation]
CVE (What is CVE?)

  1. CVE-2021-20693

  1. JVN : JVN#54025691
Revision History

  • [2021/04/14]
      Web page was published
  • [2021/05/24]
      Affected Products : Information was updated
  • [2023/03/08]
      Overview was modified