# CVE-2019-6533: Missing authorization in PR100088 Modbus gateway

> Unauthenticated attackers can read and write Modbus registers via the web interface, compromising industrial control data integrity and confidentiality.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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:** 12 Feb 2019
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-gj7v-j8r4-326v

## What is CVE-2019-6533?

CVE-2019-6533 is a critical missing authorization vulnerability in ICS-CERT PR100088 Modbus gateway, published on 12 Feb 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Registers used to store Modbus values can be read and written from the web interface without authentication in the PR100088 Modbus gateway versions prior to Release R02 (or Software Version 1.1.13166).

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2019-6533?

It affects 1 product.


Products: Kunbus Pr100088 Modbus Gateway Firmware.

## How do I fix CVE-2019-6533?

No fix has been published for CVE-2019-6533 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-6533 being exploited?

There is no known exploitation of CVE-2019-6533 in the wild and no public exploit code.

## Other vulnerabilities in ICS-CERT PR100088 Modbus gateway

- [CVE-2019-6527](https://insights.sbomify.com/CVE-2019-6527/): Auth bypass in PR100088 Modbus gateway (critical 9.8)
- [CVE-2019-6531](https://insights.sbomify.com/CVE-2019-6531/): Information disclosure in PR100088 Modbus gateway (high 8.1)
- [CVE-2019-6549](https://insights.sbomify.com/CVE-2019-6549/): Information disclosure in PR100088 Modbus gateway (high 7.2)
- [CVE-2019-6529](https://insights.sbomify.com/CVE-2019-6529/): Denial of service in PR100088 Modbus gateway (medium 4.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-6533 and fix it if it is affected.

What it is: CVE-2019-6533 is a critical missing authorization vulnerability in ICS-CERT PR100088 Modbus gateway, published on 12 Feb 2019. 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-2019-6533 in the wild and no public exploit code.

Affected product: ICS-CERT PR100088 Modbus gateway. 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-2019-6533/ (Markdown: https://insights.sbomify.com/CVE-2019-6533/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-6533
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-6533
- OSV: https://osv.dev/vulnerability/CVE-2019-6533

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-6533/
Summaries are generated and may contain mistakes; the official description above is the record.