# CVE-2021-44695: Denial of service in SIMATIC Drive Controller CPU 1504D TF

> Attackers can cause denial of service on Siemens SIMATIC PLCs by sending crafted packets to port 102/tcp.

- **Severity:** Medium 4.9 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Dec 2022
- **Updated:** 21 Apr 2025
- **Also known as:** GHSA-7hvh-r5jg-mrp9

## What is CVE-2021-44695?

CVE-2021-44695 is a medium-severity denial of service vulnerability in Siemens SIMATIC Drive Controller CPU 1504D TF, published on 13 Dec 2022. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Affected devices don't process correctly certain special crafted packets sent to port 102/tcp, which could allow an attacker to cause a denial of service in the device.

Weakness: CWE-20 (Improper Input Validation), CWE-1286 (Improper Validation of Syntactic Correctness of Input)

## Which versions are affected by CVE-2021-44695?

It affects 96 products.


Products: Siemens Simatic Et 200 Sp Open Controller Cpu 1515sp Pc Firmware, Siemens Simatic S7-1200 Cpu 1211c Firmware, Siemens Simatic S7-1200 Cpu 1212c Firmware, Siemens Simatic S7-1200 Cpu 1212fc Firmware, Siemens Simatic S7-1200 Cpu 1214 Fc Firmware, Siemens Simatic S7-1200 Cpu 1214c Firmware, Siemens Simatic S7-1200 Cpu 1214fc Firmware, Siemens Simatic S7-1200 Cpu 1215 Fc Firmware, Siemens Simatic S7-1200 Cpu 1215c Firmware, Siemens Simatic S7-1200 Cpu 1215fc Firmware, Siemens Simatic S7-1200 Cpu 1217c Firmware, Siemens Simatic S7-1200 Cpu 12 1211c Firmware, Siemens Simatic S7-1200 Cpu 12 1212c Firmware, Siemens Simatic S7-1200 Cpu 12 1212fc Firmware, Siemens Simatic S7-1200 Cpu 12 1214c Firmware, Siemens Simatic S7-1200 Cpu 12 1214fc Firmware, Siemens Simatic S7-1200 Cpu 12 1215c Firmware, Siemens Simatic S7-1200 Cpu 12 1215fc Firmware, Siemens Simatic S7-1200 Cpu 12 1217c Firmware, Siemens Simatic S7-1500 Cpu 1507s F Firmware and 76 more.

## How do I fix CVE-2021-44695?

No fix has been published for CVE-2021-44695 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-44695 being exploited?

There is no known exploitation of CVE-2021-44695 in the wild and no public exploit code.

## Other vulnerabilities in Siemens SIMATIC Drive Controller CPU 1504D TF

- [CVE-2021-40365](https://insights.sbomify.com/CVE-2021-40365/): Denial of service in SIMATIC Drive Controller CPU 1504D TF (high 7.5)
- [CVE-2021-44694](https://insights.sbomify.com/CVE-2021-44694/): Denial of service in SIMATIC Drive Controller CPU 1504D TF (medium 5.5)
- [CVE-2021-44693](https://insights.sbomify.com/CVE-2021-44693/): Denial of service in SIMATIC Drive Controller CPU 1504D TF (medium 4.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-44695 and fix it if it is affected.

What it is: CVE-2021-44695 is a medium-severity denial of service vulnerability in Siemens SIMATIC Drive Controller CPU 1504D TF, published on 13 Dec 2022. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-44695 in the wild and no public exploit code.

Affected product: Siemens SIMATIC Drive Controller CPU 1504D TF. 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-2021-44695/ (Markdown: https://insights.sbomify.com/CVE-2021-44695/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-44695
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-44695
- OSV: https://osv.dev/vulnerability/CVE-2021-44695

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-44695/
Summaries are generated and may contain mistakes; the official description above is the record.