CVE-2026-56182 is a Windows NTFS Elevation of Privilege vulnerability caused by an integer overflow or wraparound. Microsoft rates it CVSS 3.1 base 7.8 (High) with a temporal score of 6.8; the vector is LOCAL, LOW attack complexity, LOW privileges required, and no user interaction. If successfully exploited, an attacker could gain SYSTEM privileges, with HIGH confidentiality, integrity, and availability impact. Microsoft reports no public disclosure and no known exploitation, and classifies exploitation as unlikely. Because this is a local privilege escalation issue, enterprise risk is highest on systems where untrusted local code or users can run.

Highlights:
- CVSS scores: Base 7.8 - Temporal 6.8
- Exploit status & code maturity: Publicly Disclosed: No; Exploited: No; Exploit Code Maturity: UNPROVEN.
- Impact: Elevation of Privilege; attacker can gain SYSTEM privileges. Confidentiality, integrity, and availability impacts are HIGH.
- Exploitation likelihood: Exploitation Unlikely; vector is LOCAL with LOW attack complexity, LOW privileges required, and NO user interaction.
- Severity for enterprise: High CVSS severity, but risk is primarily local rather than remote. This is most relevant for hosts where local code execution or untrusted local users are possible.
- Patch status: available

Affected systems:
- Windows 10 1607
- Windows 10 1809
- Windows 10 21H2
- Windows 10 22H2
- Windows 11 24H2
- Windows 11 25H2
- Windows 11 26H1
- Windows 11 unspecified
- Windows Server 2012
- Windows Server 2012 R2
- Windows Server 2016
- Windows Server 2019
- Windows Server 2022
- Windows Server 2025