# CVE-2020-5604: Code injection in Android App 'Mercari' (Japan version)

> Remote attackers can execute arbitrary Java methods via JavaScript in WebView using reflection, enabling code execution in the Mercari Android app.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Jul 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-x466-xhx8-frqr

## What is CVE-2020-5604?

CVE-2020-5604 is a high-severity code injection vulnerability in Mercari, Inc. Android App 'Mercari' (Japan version), published on 9 Jul 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Android App 'Mercari' (Japan version) prior to version 3.52.0 allows arbitrary method execution of a Java object by a remote attacker via a Man-In-The-Middle attack by using Java Reflection API of JavaScript code on WebView.

## Which versions are affected by CVE-2020-5604?

It affects 1 product.


Products: Mercari Mercari.

## How do I fix CVE-2020-5604?

No fix has been published for CVE-2020-5604 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-5604 being exploited?

There is no known exploitation of CVE-2020-5604 in the wild and no public exploit code.

## Other vulnerabilities in Mercari, Inc. Android App 'Mercari' (Japan version)

- [CVE-2021-20835](https://insights.sbomify.com/CVE-2021-20835/): Missing authorization in Android App 'Mercari (Merpay) - Marketplace and Mobile Payments App' (Japan version) (high 7.5)
- [CVE-2024-23388](https://insights.sbomify.com/CVE-2024-23388/): Open redirect in "Mercari" App for Android (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-5604 and fix it if it is affected.

What it is: CVE-2020-5604 is a high-severity code injection vulnerability in Mercari, Inc. Android App 'Mercari' (Japan version), published on 9 Jul 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-5604 in the wild and no public exploit code.

Affected product: Mercari, Inc. Android App 'Mercari' (Japan version). No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2020-5604/ (Markdown: https://insights.sbomify.com/CVE-2020-5604/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-5604
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-5604
- OSV: https://osv.dev/vulnerability/CVE-2020-5604

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-5604/
Summaries are generated and may contain mistakes; the official description above is the record.