---
id: "CVE-2016-0099"
kind: "vulnerability"
aliases: ["CVE-2016-0099"]
title: "Microsoft Windows: Microsoft Windows Secondary Logon Service Privilege Escalation Vulnerability"
severity: "high"
cvss: 7.8
epss: 0.37045
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Microsoft Windows", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "infrastructure", "ransomware", "self-hosted", "windows"]
not_affected_if: ["patched-systems"]
published_at: "2016-03-09T11:59:09+00:00"
first_seen_at: "2026-10-23T19:11:52+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2016-0099", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2016-0099", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2016-0099", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Microsoft Windows: Microsoft Windows Secondary Logon Service Privilege Escalation Vulnerability

Windows Secondary Logon Service mishandles request handles in memory, allowing local privilege escalation. An attacker who already has a local foothold can run arbitrary code as an administrator.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Microsoft Windows affected ? fixed ?

## Fix

Apply the Microsoft security update for CVE-2016-0099 per vendor instructions (CISA KEV required action). Specific KB numbers are unknown from the sources.

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2016-0099
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2016-0099
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2016-0099

## From the sources

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."

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_