niconico App for iOS fails to verify SSL server certificates


niconico App for iOS provided by DWANGO Co., Ltd. fails to verify SSL server certificates.

AOKI Keiichi 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 4.0 (Medium) [IPA Score]
  • Access Vector: Network
  • Access Complexity: High
  • Authentication: None
  • Confidentiality Impact: Partial
  • Integrity Impact: Partial
  • Availability Impact: None
Affected Products

DWANGO Co., Ltd.
  • niconico App for iOS version 6.37 and earlier


A man-in-the-middle attack may allow an attacker to eavesdrop on an encrypted communication.

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

DWANGO Co., Ltd.
CWE (What is CWE?)

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

  1. CVE-2015-5639

  1. JVN : JVN#20355129
  2. National Vulnerability Database (NVD) : CVE-2015-5639
Revision History

  • [2015/09/29]
      Web page was published
  • [2018/03/07]
      References : Content was added