# CVE-2016-0099: Microsoft Windows Secondary Logon Service Privilege Escalation

> Local attackers can gain elevated privileges by exploiting improper handle processing in the Windows Secondary Logon Service.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 3 Mar 2022 (CISA KEV), used in ransomware
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Mar 2016
- **Updated:** 21 Oct 2025
- **Also known as:** GHSA-fq5j-826m-h5wc

## What is CVE-2016-0099?

CVE-2016-0099 is a high-severity vulnerability in Microsoft Windows 10 1507, published on 9 Mar 2016. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The Secondary Logon Service in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, and Windows 10 Gold and 1511 does not properly process request handles, which allows local users to gain privileges via a crafted application, aka "Secondary Logon Elevation of Privilege Vulnerability."

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2016-0099?

It affects 7 products.


Products: Microsoft Windows 10 1507, Microsoft Windows 10 1511, Microsoft Windows 7, Microsoft Windows 8.1, Microsoft Windows Server 2008, Microsoft Windows Server 2012, Microsoft Windows Vista.

## How do I fix CVE-2016-0099?

No fix has been published for CVE-2016-0099 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 24 Mar 2022.

## Is CVE-2016-0099 being exploited?

Yes. Attackers have exploited CVE-2016-0099 in the wild since at least 3 Mar 2022, including in ransomware campaigns.

Public exploit code:

- MS16-032(CVE-2016-0099) for SERVICE ONLY (github_poc): https://github.com/zcgonvh/MS16-032
- Microsoft Windows 8.1/10 (x86) - Secondary Logon Standard Handles Missing Sanitization Privilege Escalation (MS16-032) (exploitdb)
- MS16-032 Secondary Logon Handle Privilege Escalation (metasploit)
- Microsoft Windows 7 < 10 / 2008 < 2012 R2 (x86/x64) - Local Privilege Escalation (MS16-032) (PowerShell) (exploitdb)
- Microsoft Windows 7 < 10 / 2008 < 2012 (x86/x64) - Local Privilege Escalation (MS16-032) (exploitdb)
- Microsoft Windows 7 < 10 / 2008 < 2012 (x86/x64) - Secondary Logon Handle Privilege Escalation (MS16-032) (Metasploit) (exploitdb)

## Other vulnerabilities in Microsoft Windows 10 1507

- [CVE-2017-8543](https://insights.sbomify.com/CVE-2017-8543/): Microsoft Windows Search Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2025-33053](https://insights.sbomify.com/CVE-2025-33053/): Microsoft Windows External Control of File Name or Path (high 8.8, exploited in the wild)
- [CVE-2025-33073](https://insights.sbomify.com/CVE-2025-33073/): Microsoft Windows SMB Client Improper Access Control (high 8.8, exploited in the wild)
- [CVE-2024-49039](https://insights.sbomify.com/CVE-2024-49039/): Microsoft Windows Task Scheduler Privilege Escalation (high 8.8, exploited in the wild)
- [CVE-2024-43461](https://insights.sbomify.com/CVE-2024-43461/): Microsoft Windows MSHTML Platform Spoofing (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-0099 and fix it if it is affected.

What it is: CVE-2016-0099 is a high-severity vulnerability in Microsoft Windows 10 1507, published on 9 Mar 2016. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2016-0099 in the wild since at least 3 Mar 2022, including in ransomware campaigns.

Affected product: Microsoft Windows 10 1507. 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-2016-0099/ (Markdown: https://insights.sbomify.com/CVE-2016-0099/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-0099
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-0099
- OSV: https://osv.dev/vulnerability/CVE-2016-0099

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-0099/
Summaries are generated and may contain mistakes; the official description above is the record.