CVE-2026-50308 is a Windows NTFS remote code execution vulnerability described as an integer underflow (wrap or wraparound). Microsoft rates it at CVSS v3.1 base 7.8 (High) with a temporal score of 6.8. The vector is local access, low attack complexity, no privileges required, and user interaction required. Exploit status is not publicly disclosed and not known to be exploited, with exploit code maturity listed as unproven. The issue can lead to high confidentiality, integrity, and availability impact if successfully exploited, but the local vector and required user interaction reduce immediate exposure compared with network-reachable remote code execution issues.

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 with HIGH confidentiality, HIGH integrity, and HIGH availability impact.
- Exploitation likelihood: Exploitation Unlikely; 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-exposed RCE because exploitation requires local access and user interaction.
- 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