# CVE-2021-20589: Denial of service in GOT2000 series; GOT SIMPLE series; GT SoftGOT2000; Tension Controller

> Remote unauthenticated attackers can stop communication functions in Mitsubishi GOT and Tension Controller devices via crafted packets.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/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:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 May 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-q2w2-jjv8-fvww

## What is CVE-2021-20589?

CVE-2021-20589 is a high-severity denial of service vulnerability in GOT2000 series; GOT SIMPLE series; GT SoftGOT2000; Tension Controller, published on 19 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Buffer access with incorrect length value vulnerability in GOT2000 series GT27 model communication driver versions 01.19.000 through 01.38.000, GT25 model communication driver versions 01.19.000 through 01.38.000, GT23 model communication driver versions 01.19.000 through 01.38.000 and GT21 model communication driver versions 01.21.000 through 01.39.000, GOT SIMPLE series GS21 model communication driver versions 01.21.000 through 01.39.000, GT SoftGOT2000 versions 1.170C through 1.250L and Tension Controller LE7-40GU-L Screen package data for MODBUS/TCP V1.00 allows a remote unauthenticated attacker to stop the communication function of the products via specially crafted packets.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2021-20589?

It affects 6 products.


Products: Mitsubishi Gs21 Firmware, Mitsubishi Gt21 Firmware, Mitsubishi Gt23 Firmware, Mitsubishi Gt25 Firmware, Mitsubishi Gt27 Firmware, Mitsubishi Gt Softgot2000 Firmware.

## How do I fix CVE-2021-20589?

No fix has been published for CVE-2021-20589 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20589 being exploited?

There is no known exploitation of CVE-2021-20589 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20589 and fix it if it is affected.

What it is: CVE-2021-20589 is a high-severity denial of service vulnerability in GOT2000 series; GOT SIMPLE series; GT SoftGOT2000; Tension Controller, published on 19 May 2021. 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-2021-20589 in the wild and no public exploit code.

Affected product: GOT2000 series; GOT SIMPLE series; GT SoftGOT2000; Tension Controller. 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-2021-20589/ (Markdown: https://insights.sbomify.com/CVE-2021-20589/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20589
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20589
- OSV: https://osv.dev/vulnerability/CVE-2021-20589

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-20589/
Summaries are generated and may contain mistakes; the official description above is the record.