# CVE-2016-20033: Wowza Streaming Engine 4.5.0 Local Privilege Escalation via nssm_x64.exe

> Authenticated local attackers can escalate privileges to LocalSystem by replacing service executables due to insecure file permissions.

- **Severity:** High 8.5 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Mar 2026
- **Updated:** 16 Mar 2026
- **Also known as:** GHSA-fmp5-4w5p-wx24

## What is CVE-2016-20033?

CVE-2016-20033 is a high-severity vulnerability in Wowza Streaming Engine, published on 15 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Wowza Streaming Engine 4.5.0 contains a local privilege escalation vulnerability that allows authenticated users to escalate privileges by replacing executable files due to improper file permissions granting full access to the Everyone group. Attackers can replace the nssm_x64.exe binary in the manager and engine service directories with malicious executables to execute code with LocalSystem privileges when services restart.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2016-20033?

It affects 1 product.


Products: Wowza Streaming Engine.

## How do I fix CVE-2016-20033?

No fix has been published for CVE-2016-20033 yet. Limit exposure of the affected software until one is available.

## Is CVE-2016-20033 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-20033 exists.

## Other vulnerabilities in Wowza Streaming Engine

- [CVE-2018-7047](https://insights.sbomify.com/CVE-2018-7047/): Hardcoded credentials in n/a (critical 9.8)
- [CVE-2024-52052](https://insights.sbomify.com/CVE-2024-52052/): Stream Target Remote Code Execution in Wowza Streaming Engine (critical 9.4)
- [CVE-2018-19365](https://insights.sbomify.com/CVE-2018-19365/): Path traversal in n/a (critical 9.1)
- [CVE-2020-9004](https://insights.sbomify.com/CVE-2020-9004/): Auth bypass in n/a (high 8.8)
- [CVE-2016-20034](https://insights.sbomify.com/CVE-2016-20034/): Wowza Streaming Engine 4.5.0 Privilege Escalation via user edit (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-20033 and fix it if it is affected.

What it is: CVE-2016-20033 is a high-severity vulnerability in Wowza Streaming Engine, published on 15 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-20033 exists.

Affected product: Wowza Streaming Engine. 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-2016-20033/ (Markdown: https://insights.sbomify.com/CVE-2016-20033/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-20033
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-20033
- OSV: https://osv.dev/vulnerability/CVE-2016-20033

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-20033/
Summaries are generated and may contain mistakes; the official description above is the record.