CVE-2026-50402 is an NTFS elevation of privilege vulnerability caused by incorrect conversion between numeric types. 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 attack only, with low attack complexity, low privileges required, and no user interaction. If exploited, it can affect confidentiality, integrity, and availability at high levels. Microsoft reports no public disclosure, no known exploitation, and exploit code maturity is unproven. Because the issue is local-only, enterprise risk is centered on systems where untrusted local code or users can obtain access.

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 Unlikely; local attack vector with LOW attack complexity, LOW privileges required, and NO user interaction
- Severity for enterprise: High severity by CVSS, but lower exposure than network-based vulnerabilities because exploitation requires local access
- Patch status: available; customer action 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