"Rikunabi NEXT" App for Android fails to restrict custom URL schemes properly


"Rikunabi NEXT" App for Android provided by Recruit Co., Ltd. provides the function to access a requested URL using Custom URL Scheme. The App does not restrict access to the function properly (CWE-939) which may be exploited to direct the App to access any sites.

Nao Komatsu of LAC Co., Ltd. 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 4.3 (Medium) [IPA Score]
  • Attack Vector: Network
  • 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

  • "Rikunabi NEXT" App for Android prior to ver. 11.5.0


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.
The developer has released the following version that fixes the vulnerability.

* "Rikunabi NEXT" App for Android ver. 11.5.0
Vendor Information

CWE (What is CWE?)

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

  1. CVE-2023-39507

  1. JVN : JVN#84820712
  2. National Vulnerability Database (NVD) : CVE-2023-39507
Revision History

  • [2023/08/09]
      Web page was published
  • [2024/03/28]
      References : Content was added