CVE-2026-56175 is a Windows NTFS elevation of privilege vulnerability described as a heap-based buffer overflow. Microsoft rates it High severity with a CVSS v3.1 base score of 7.8 and temporal score of 6.8. The vector is local (AV:L), low complexity, requires low privileges, and no user interaction. The impact is high for confidentiality, integrity, and availability. Microsoft says there is no public disclosure and no known exploitation, with exploit code maturity unproven. This is primarily a local attack risk rather than a network-exposed service risk, so enterprise exposure is highest on systems where untrusted local access is possible.

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; confidentiality, integrity, and availability impacts are all HIGH.
- Exploitation likelihood: Exploitation Less Likely, with a LOCAL vector, LOW attack complexity, LOW privileges required, and NO user interaction.
- Severity for enterprise: High technical severity, but practical enterprise risk is lower than network-reachable flaws because exploitation requires local access. Risk is more relevant on multi-user systems, endpoints with untrusted local code, or shared Windows server environments.
- Patch status: available; customer action is required.

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