# CVE-2021-33728: Deserialization in SINEC NMS

> A privileged attacker can execute arbitrary code with root privileges on Siemens SINEC NMS via insecure deserialization of crafted Java objects.

- **Severity:** High 7.2 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Oct 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-6ccq-w7mc-g74j

## What is CVE-2021-33728?

CVE-2021-33728 is a high-severity unsafe deserialization vulnerability in Siemens SINEC NMS, published on 12 Oct 2021. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

A vulnerability has been identified in SINEC NMS (All versions < V1.0 SP2 Update 1). The affected system allows to upload JSON objects that are deserialized to JAVA objects. Due to insecure deserialization of user-supplied content by the affected software, a privileged attacker could exploit this vulnerability by sending a crafted serialized Java object. An exploit could allow the attacker to execute arbitrary code on the device with root privileges.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2021-33728?

It affects 1 product.


Products: Siemens Sinec Nms.

## How do I fix CVE-2021-33728?

No fix has been published for CVE-2021-33728 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-33728 being exploited?

There is no known exploitation of CVE-2021-33728 in the wild and no public exploit code.

## Other vulnerabilities in Siemens SINEC NMS

- [CVE-2024-41940](https://insights.sbomify.com/CVE-2024-41940/): Command injection in SINEC NMS (critical 9.4)
- [CVE-2025-40736](https://insights.sbomify.com/CVE-2025-40736/): Missing authorization in SINEC NMS (critical 9.3)
- [CVE-2021-33724](https://insights.sbomify.com/CVE-2021-33724/): Path traversal in SINEC NMS (critical 9.1)
- [CVE-2021-33725](https://insights.sbomify.com/CVE-2021-33725/): Path traversal in SINEC NMS (critical 9.1)
- [CVE-2024-23810](https://insights.sbomify.com/CVE-2024-23810/): SQL injection in SINEC NMS (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-33728 and fix it if it is affected.

What it is: CVE-2021-33728 is a high-severity unsafe deserialization vulnerability in Siemens SINEC NMS, published on 12 Oct 2021. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-33728 in the wild and no public exploit code.

Affected product: Siemens SINEC NMS. 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-2021-33728/ (Markdown: https://insights.sbomify.com/CVE-2021-33728/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-33728
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-33728
- OSV: https://osv.dev/vulnerability/CVE-2021-33728

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-33728/
Summaries are generated and may contain mistakes; the official description above is the record.