CVE-2016-0099VulnerabilityPublished 03/03/2022Updated 10/24/2026

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

Affects Microsoft WindowsSource CISA KEV

Severity

High

No CVSS score published yet

Exploitation: Actively exploited – in CISA KEV since 03/03/2022
KEV deadline: 03/24/2022
Ransomware: Used in ransomware campaigns
EPSS: 37.0% chance of exploitation in 30 days – higher than 98% of CVEs

What to do

CISA required action

Apply updates per vendor instructions.

nvd.nist.gov/vuln/detail/CVE-2016-0099 (opens in a new tab)

Description

CVE-2016-0099 is a privilege escalation vulnerability in Microsoft Windows involving the Secondary Logon Service's improper management of request handles in memory. Successful exploitation allows an attacker to execute arbitrary code with administrator privileges. This vulnerability has been exploited in the wild and is associated with known ransomware campaigns.

Summary

This vulnerability arises from the Windows Secondary Logon Service failing to properly manage request handles in memory, enabling privilege escalation. An attacker exploiting this flaw can run arbitrary code with elevated administrator rights. The vulnerability is tracked as CVE-2016-0099 and has been observed in active exploitation scenarios, including ransomware campaigns.

Impact

Exploitation of this vulnerability allows attackers to gain administrator-level code execution on affected Windows systems, potentially leading to full system compromise. It has been used in the wild, including in ransomware attacks, indicating active threat exploitation.

Mitigation

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no patch links or official remediation information are provided, users should monitor Microsoft advisories for updates and apply any available security updates promptly.

Weaknesses

CWE-264Unclassified weakness (opens in a new tab)

What to do

Description

AnalysisAI-generated, updated 10/24/2026, 10:26:23 UTC

Weaknesses

References

Related threats