# CVE-2021-33716: Information disclosure in SIMATIC CP 1543-1 (incl. SIPLUS variants)

> An attacker on the local subnet can retrieve sensitive information stored in cleartext from affected Siemens SIMATIC communication processors.

- **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:** 14 Sep 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-9mhw-hmhp-8rm5

## What is CVE-2021-33716?

CVE-2021-33716 is a medium-severity vulnerability in Siemens SIMATIC CP 1543-1 (incl. SIPLUS variants), published on 14 Sep 2021. 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 CP 1543-1 (incl. SIPLUS variants) (All versions < V3.0), SIMATIC CP 1545-1 (All versions < V1.1). An attacker with access to the subnet of the affected device could retrieve sensitive information stored in cleartext.

Weakness: CWE-312 (Cleartext Storage of Sensitive Information)

## Which versions are affected by CVE-2021-33716?

It affects 2 products.


Products: Siemens Simatic Cp 1543-1 Firmware, Siemens Simatic Cp 1545-1 Firmware.

## How do I fix CVE-2021-33716?

No fix has been published for CVE-2021-33716 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-33716 being exploited?

There is no known exploitation of CVE-2021-33716 in the wild and no public exploit code.

## Other vulnerabilities in Siemens SIMATIC CP 1543-1 (incl. SIPLUS variants)

- [CVE-2016-8562](https://insights.sbomify.com/CVE-2016-8562/): Siemens SIMATIC CP 1543-1 Improper Privilege Management (high 7.5, exploited in the wild)
- [CVE-2024-50310](https://insights.sbomify.com/CVE-2024-50310/): Missing authorization in SIMATIC CP 1543-1 V4.0 (high 8.7)
- [CVE-2016-8561](https://insights.sbomify.com/CVE-2016-8561/): Privilege escalation in n/a (medium 6.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-33716 and fix it if it is affected.

What it is: CVE-2021-33716 is a medium-severity vulnerability in Siemens SIMATIC CP 1543-1 (incl. SIPLUS variants), published on 14 Sep 2021. 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-2021-33716 in the wild and no public exploit code.

Affected product: Siemens SIMATIC CP 1543-1 (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-2021-33716/ (Markdown: https://insights.sbomify.com/CVE-2021-33716/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-33716
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-33716
- OSV: https://osv.dev/vulnerability/CVE-2021-33716

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-33716/
Summaries are generated and may contain mistakes; the official description above is the record.