Headline
CVE-2021-20835: JVN#49465877: Android App "Mercari (Merpay)
Improper authorization in handler for custom URL scheme vulnerability in Android App ‘Mercari (Merpay) - Marketplace and Mobile Payments App’ (Japan version) versions prior to 4.49.1 allows a remote attacker to lead a user to access an arbitrary website and the website launches an arbitrary Activity of the app via the vulnerable App, which may result in Mercari account’s access token being obtained.
Published:2021/10/29 Last Updated:2021/11/24
**JVN#49465877
Android App “Mercari (Merpay) - Marketplace and Mobile Payments App” (Japan version) vulnerable to improper handling of Intent
**
Overview
Android App “Mercari (Merpay) - Marketplace and Mobile Payments App” (Japan version) is vulnerable to improper handling of Intent.
Products Affected
- Android App “Mercari (Merpay) - Marketplace and Mobile Payments App” (Japan version) versions prior to 4.49.1
The developer states that affected versions are no longer used at this point because the update was applied automatically when the application was launched in the past.
Description
Android App “Mercari (Merpay) - Marketplace and Mobile Payments App” (Japan version) provided by Mercari, Inc. is vulnerable to improper handling of Intent (CWE-939).
Impact
If a user who is using the vulnerable application accesses a malicious page, the malicious page can launch an arbitrary Activity of the application. As a result, Mercari account’s access token may be obtained.
Solution
Update the application
Update the application to the latest version according to the information provided by the developer.
The developer states there is no need for users to take any actions since the application is automatically updated when it is launched.
Vendor Status
Vendor
Status
Last Update
Vendor Notes
Mercari, Inc.
Vulnerable
2021/10/29
References
JPCERT/CC Addendum
Vulnerability Analysis by JPCERT/CC
CVSS v3 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N
Attack Vector(AV)
Physical §
Local (L)
Adjacent (A)
Network (N)
Attack Complexity(AC)
High (H)
Low (L)
Privileges Required(PR)
High (H)
Low (L)
None (N)
User Interaction(UI)
Required ®
None (N)
Scope(S)
Unchanged (U)
Changed ©
Confidentiality Impact©
None (N)
Low (L)
High (H)
Integrity Impact(I)
None (N)
Low (L)
High (H)
Availability Impact(A)
None (N)
Low (L)
High (H)
CVSS v2 AV:N/AC:M/Au:N/C:P/I:N/A:N
Access Vector(AV)
Local (L)
Adjacent Network (A)
Network (N)
Access Complexity(AC)
High (H)
Medium (M)
Low (L)
Authentication(Au)
Multiple (M)
Single (S)
None (N)
Confidentiality Impact©
None (N)
Partial §
Complete ©
Integrity Impact(I)
None (N)
Partial §
Complete ©
Availability Impact(A)
None (N)
Partial §
Complete ©
Credit
RyotaK reported this vulnerability to Mercari, Inc. and Mercari, Inc. reported it to JPCERT/CC to disclose the vulnerability through JVN.
Other Information
Update History
2021/11/24
Information under the section [Vulnerability Analysis by JPCERT/CC] was added.