CVE-2026-50448 is a Windows NTFS heap-based buffer overflow that Microsoft describes as a remote code execution vulnerability. The CVSS v3.1 base score is 7.8 (High) with a temporal score of 6.8. The vector is local, requires no privileges but does require user interaction, and has high confidentiality, integrity, and availability impact. Microsoft says the issue is not publicly disclosed, not exploited, and exploit code maturity is unproven. The FAQ states the user must mount a .vhd file for compromise, which makes this a phishing/social-engineering-dependent local attack rather than a network-exposed service issue. Customer action is required.

Highlights:
- CVSS scores: Base 7.8 - Temporal 6.8
- Exploit status & code maturity: Publicly Disclosed: No; Exploited: No; Exploit Code Maturity: UNPROVEN.
- Impact: Remote Code Execution; confidentiality, integrity, and availability impacts are all HIGH.
- Exploitation likelihood: Exploitation Less Likely; vector context is LOCAL with LOW attack complexity, NO privileges required, and USER INTERACTION required.
- Severity for enterprise: High severity by CVSS, but real-world enterprise risk is lower than network-reachable RCE because exploitation requires local interaction and mounting a specially crafted .vhd file.
- 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