# CVE-2021-20607: Integer overflow in Mitsubishi Electric GX Works2; Mitsubishi Electric MELSOFT Navigator; Mitsubishi Electric EZSocket

> An attacker can cause a denial of service in Mitsubishi Electric PLC programming software by tricking a user into opening a maliciously crafted project file.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 17 Dec 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-c5g3-qqp2-f4cv

## What is CVE-2021-20607?

CVE-2021-20607 is a medium-severity vulnerability in Mitsubishi Electric GX Works2; Mitsubishi Electric MELSOFT Navigator; Mitsubishi Electric EZSocket, published on 17 Dec 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Integer Underflow vulnerability in Mitsubishi Electric GX Works2 versions 1.606G and prior, Mitsubishi Electric MELSOFT Navigator versions 2.84N and prior and Mitsubishi Electric EZSocket versions 5.4 and prior allows an attacker to cause a DoS condition in the software by getting a user to open malicious project file specially crafted by an attacker.

Weakness: CWE-191 (Integer Underflow (Wrap or Wraparound))

## Which versions are affected by CVE-2021-20607?

It affects 3 products.


Products: Mitsubishielectric Ezsocket, Mitsubishielectric Gx Works2, Mitsubishielectric Melsoft Navigator.

## How do I fix CVE-2021-20607?

No fix has been published for CVE-2021-20607 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20607 being exploited?

There is no known exploitation of CVE-2021-20607 in the wild and no public exploit code.

## Other vulnerabilities in Mitsubishi Electric GX Works2; Mitsubishi Electric MELSOFT Navigator; Mitsubishi Electric EZSocket

- [CVE-2023-6943](https://insights.sbomify.com/CVE-2023-6943/): Code injection in EZSocket (critical 9.8)
- [CVE-2023-6942](https://insights.sbomify.com/CVE-2023-6942/): Auth bypass in EZSocket (high 7.5)
- [CVE-2021-20606](https://insights.sbomify.com/CVE-2021-20606/): Denial of service in Mitsubishi Electric GX Works2; Mitsubishi Electric MELSOFT Navigator; Mitsubishi Electric EZSocket (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20607 and fix it if it is affected.

What it is: CVE-2021-20607 is a medium-severity vulnerability in Mitsubishi Electric GX Works2; Mitsubishi Electric MELSOFT Navigator; Mitsubishi Electric EZSocket, published on 17 Dec 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-20607 in the wild and no public exploit code.

Affected product: Mitsubishi Electric GX Works2; Mitsubishi Electric MELSOFT Navigator; Mitsubishi Electric EZSocket. 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-2021-20607/ (Markdown: https://insights.sbomify.com/CVE-2021-20607/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20607
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20607
- OSV: https://osv.dev/vulnerability/CVE-2021-20607

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-20607/
Summaries are generated and may contain mistakes; the official description above is the record.