# CVE-2020-25241: Denial of service in SIMATIC MV400 family

> An attacker can terminate arbitrary TCP sessions by exploiting improper validation of TCP RST sequence numbers in SIMATIC MV400 devices.

- **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:** 15 Mar 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-hgp9-8qfr-qjj7

## What is CVE-2020-25241?

CVE-2020-25241 is a high-severity denial of service vulnerability in Siemens SIMATIC MV400 family, published on 15 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability has been identified in SIMATIC MV400 family (All Versions < V7.0.6). The underlying TCP stack of the affected products does not correctly validate the sequence number for incoming TCP RST packages. An attacker could exploit this to terminate arbitrary TCP sessions.

Weakness: CWE-129 (Improper Validation of Array Index), CWE-1285 (Improper Validation of Specified Index, Position, or Offset in Input)

## Which versions are affected by CVE-2020-25241?

It affects 7 products.


Products: Siemens Simatic Mv420 Sr-B Body Firmware, Siemens Simatic Mv420 Sr-B Firmware, Siemens Simatic Mv420 Sr-P Body Firmware, Siemens Simatic Mv420 Sr-P Firmware, Siemens Simatic Mv440 Hr Firmware, Siemens Simatic Mv440 Sr Firmware, Siemens Simatic Mv440 Ur Firmware.

## How do I fix CVE-2020-25241?

No fix has been published for CVE-2020-25241 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-25241 being exploited?

There is no known exploitation of CVE-2020-25241 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-25241 and fix it if it is affected.

What it is: CVE-2020-25241 is a high-severity denial of service vulnerability in Siemens SIMATIC MV400 family, published on 15 Mar 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-2020-25241 in the wild and no public exploit code.

Affected product: Siemens SIMATIC MV400 family. 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-2020-25241/ (Markdown: https://insights.sbomify.com/CVE-2020-25241/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-25241
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-25241
- OSV: https://osv.dev/vulnerability/CVE-2020-25241

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-25241/
Summaries are generated and may contain mistakes; the official description above is the record.