# CVE-2020-5657: Command injection in MELSEC iQ-R series

> Unauthenticated attackers on adjacent networks can cause denial of service in Mitsubishi MELSEC iQ-R modules via argument injection in TCP/IP functions.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/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:** Not needed
- **Fix available:** No
- **Published:** 30 Oct 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-wwhv-765h-78r7

## What is CVE-2020-5657?

CVE-2020-5657 is a medium-severity command injection vulnerability in Mitsubishi Electric Corporation MELSEC iQ-R series, published on 30 Oct 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Improper neutralization of argument delimiters in a command ('Argument Injection') vulnerability in TCP/IP function included in the firmware of MELSEC iQ-R series (RJ71EIP91 EtherNet/IP Network Interface Module First 2 digits of serial number are '02' or before, RJ71PN92 PROFINET IO Controller Module First 2 digits of serial number are '01' or before, RD81DL96 High Speed Data Logger Module First 2 digits of serial number are '08' or before, RD81MES96N MES Interface Module First 2 digits of serial number are '04' or before, and RD81OPC96 OPC UA Server Module First 2 digits of serial number are '04' or before) allows unauthenticated attackers on adjacent network to stop the network functions of the products via a specially crafted packet.

Weakness: CWE-88 (Improper Neutralization of Argument Delimiters in a Command)

## Which versions are affected by CVE-2020-5657?

It affects 5 products.


Products: Mitsubishielectric Melsec Iq-Rd81dl96 Firmware, Mitsubishielectric Melsec Iq-Rd81mes96n Firmware, Mitsubishielectric Melsec Iq-Rd81opc96 Firmware, Mitsubishielectric Melsec Iq-Rj71eip91 Firmware, Mitsubishielectric Melsec Iq-Rj71pn92 Firmware.

## How do I fix CVE-2020-5657?

No fix has been published for CVE-2020-5657 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-5657 being exploited?

There is no known exploitation of CVE-2020-5657 in the wild and no public exploit code.

## Other vulnerabilities in Mitsubishi Electric Corporation MELSEC iQ-R series

- [CVE-2020-5653](https://insights.sbomify.com/CVE-2020-5653/): Memory corruption in MELSEC iQ-R series (critical 9.8)
- [CVE-2020-5656](https://insights.sbomify.com/CVE-2020-5656/): Missing authorization in MELSEC iQ-R series (critical 9.8)
- [CVE-2020-5654](https://insights.sbomify.com/CVE-2020-5654/): Auth bypass in MELSEC iQ-R series (high 7.5)
- [CVE-2020-5655](https://insights.sbomify.com/CVE-2020-5655/): Null dereference in MELSEC iQ-R series (high 7.5)
- [CVE-2020-5658](https://insights.sbomify.com/CVE-2020-5658/): Denial of service in MELSEC iQ-R series (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-5657 and fix it if it is affected.

What it is: CVE-2020-5657 is a medium-severity command injection vulnerability in Mitsubishi Electric Corporation MELSEC iQ-R series, published on 30 Oct 2020. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-5657 in the wild and no public exploit code.

Affected product: Mitsubishi Electric Corporation MELSEC iQ-R series. 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-2020-5657/ (Markdown: https://insights.sbomify.com/CVE-2020-5657/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-5657
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-5657
- OSV: https://osv.dev/vulnerability/CVE-2020-5657

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-5657/
Summaries are generated and may contain mistakes; the official description above is the record.