# CVE-2020-15791: Information disclosure in SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants)

> An attacker can intercept network traffic to obtain valid PLC credentials due to insufficient protection in the authentication protocol.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **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:** 9 Sep 2020
- **Updated:** 2 Jun 2026
- **Also known as:** GHSA-8qxp-fp5j-5wxj

## What is CVE-2020-15791?

CVE-2020-15791 is a medium-severity vulnerability in Siemens SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants), published on 9 Sep 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability has been identified in SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions), SIMATIC S7-400 CPU family (incl. SIPLUS variants) (All versions), SIMATIC WinAC RTX (F) 2010 (All versions), SINUMERIK 840D sl (All versions). The authentication protocol between a client and a PLC via port 102/tcp (ISO-TSAP) insufficiently protects the transmitted password. This could allow an attacker that is able to intercept the network traffic to obtain valid PLC credentials.

Weakness: CWE-522 (Insufficiently Protected Credentials)

## Which versions are affected by CVE-2020-15791?

It affects 14 products.


Products: Siemens Simatic S7-300 Cpu 312 Firmware, Siemens Simatic S7-300 Cpu 314 Firmware, Siemens Simatic S7-300 Cpu 315-2 Dp Firmware, Siemens Simatic S7-300 Cpu 315-2 Pn Firmware, Siemens Simatic S7-300 Cpu 315f-2 Dp Firmware, Siemens Simatic S7-300 Cpu 315f-2 Pn Firmware, Siemens Simatic S7-300 Cpu 317-2 Dp Firmware, Siemens Simatic S7-300 Cpu 317-2 Pn Firmware, Siemens Simatic S7-300 Cpu 317f-2 Dp Firmware, Siemens Simatic S7-300 Cpu 317f-2 Pn Firmware, Siemens Simatic S7-400 Cpu 412 Firmware, Siemens Simatic S7-400 Cpu 414 Firmware, Siemens Simatic S7-400 Cpu 416 Firmware, Siemens Simatic S7-400 Cpu 417 Firmware.

## How do I fix CVE-2020-15791?

No fix has been published for CVE-2020-15791 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-15791 being exploited?

There is no known exploitation of CVE-2020-15791 in the wild and no public exploit code.

## Other vulnerabilities in Siemens SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants)

- [CVE-2020-15783](https://insights.sbomify.com/CVE-2020-15783/): Denial of service in SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants) (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-15791 and fix it if it is affected.

What it is: CVE-2020-15791 is a medium-severity vulnerability in Siemens SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants), published on 9 Sep 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-2020-15791 in the wild and no public exploit code.

Affected product: Siemens SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants). 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-2020-15791/ (Markdown: https://insights.sbomify.com/CVE-2020-15791/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-15791
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-15791
- OSV: https://osv.dev/vulnerability/CVE-2020-15791

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-15791/
Summaries are generated and may contain mistakes; the official description above is the record.