# CVE-2011-20001: Denial of service in SIMATIC S7-1200 CPU V1 family (incl. SIPLUS variants)

> Unauthenticated remote attackers can cause denial of service on Siemens SIMATIC S7-1200 CPUs by sending malformed HTTP traffic.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Oct 2025
- **Updated:** 14 Oct 2025
- **Also known as:** GHSA-hfrj-93xv-cmrv

## What is CVE-2011-20001?

CVE-2011-20001 is a high-severity denial of service vulnerability in Siemens SIMATIC S7-1200 CPU V1 family (incl. SIPLUS variants), published on 14 Oct 2025. 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 S7-1200 CPU V1 family (incl. SIPLUS variants) (All versions < V2.0.3), SIMATIC S7-1200 CPU V2 family (incl. SIPLUS variants) (All versions < V2.0.3). The web server interface of affected devices improperly processes incoming malformed HTTP traffic at high rate. This could allow an unauthenticated remote attacker to force the device entering the stop/defect state, thus creating a denial of service condition.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2011-20001?


## How do I fix CVE-2011-20001?

No fix has been published for CVE-2011-20001 yet. Limit exposure of the affected software until one is available.

## Is CVE-2011-20001 being exploited?

There is no known exploitation of CVE-2011-20001 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-20001 and fix it if it is affected.

What it is: CVE-2011-20001 is a high-severity denial of service vulnerability in Siemens SIMATIC S7-1200 CPU V1 family (incl. SIPLUS variants), published on 14 Oct 2025. 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-2011-20001 in the wild and no public exploit code.

Affected product: Siemens SIMATIC S7-1200 CPU V1 family (incl. 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-2011-20001/ (Markdown: https://insights.sbomify.com/CVE-2011-20001/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-20001
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-20001
- OSV: https://osv.dev/vulnerability/CVE-2011-20001

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From sbomify Insights: https://insights.sbomify.com/CVE-2011-20001/
Summaries are generated and may contain mistakes; the official description above is the record.