# CVE-2021-20590: Auth bypass in GOT SIMPLE series GS21 model GS2107-WTBD-N

> Remote attackers can bypass authentication to gain unauthorized access to Mitsubishi GOT HMI devices via VNC when the feature is enabled.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Apr 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-p459-vh9f-cr64

## What is CVE-2021-20590?

CVE-2021-20590 is a high-severity authentication bypass vulnerability in GOT SIMPLE series GS21 model GS2107-WTBD-N, published on 22 Apr 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Improper authentication vulnerability in GOT2000 series GT27 model VNC server versions 01.39.010 and prior, GOT2000 series GT25 model VNC server versions 01.39.010 and prior, GOT2000 series GT21 model GT2107-WTBD VNC server versions 01.40.000 and prior, GOT2000 series GT21 model GT2107-WTSD VNC server versions 01.40.000 and prior, GOT SIMPLE series GS21 model GS2110-WTBD-N VNC server versions 01.40.000 and prior and GOT SIMPLE series GS21 model GS2107-WTBD-N VNC server versions 01.40.000 and prior allows a remote unauthenticated attacker to gain unauthorized access via specially crafted packets when the "VNC server" function is used.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2021-20590?

It affects 6 products.


Products: Mitsubishielectric Got2000 Gt25 Firmware, Mitsubishielectric Got2000 Gt27 Firmware, Mitsubishielectric Gs2107-Wtbd-N Firmware, Mitsubishielectric Gs2110-Wtbd-N Firmware, Mitsubishielectric Gt2107-Wtbd Firmware, Mitsubishielectric Gt2107-Wtsd Firmware.

## How do I fix CVE-2021-20590?

No fix has been published for CVE-2021-20590 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20590 being exploited?

There is no known exploitation of CVE-2021-20590 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20590 and fix it if it is affected.

What it is: CVE-2021-20590 is a high-severity authentication bypass vulnerability in GOT SIMPLE series GS21 model GS2107-WTBD-N, published on 22 Apr 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-2021-20590 in the wild and no public exploit code.

Affected product: GOT SIMPLE series GS21 model GS2107-WTBD-N. 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-2021-20590/ (Markdown: https://insights.sbomify.com/CVE-2021-20590/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20590
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20590
- OSV: https://osv.dev/vulnerability/CVE-2021-20590

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-20590/
Summaries are generated and may contain mistakes; the official description above is the record.