CVE-2026-50311 is a Windows Server elevation of privilege vulnerability caused by improper access control. Microsoft rates it High severity with a CVSS v3.1 base score of 7.8 and temporal score of 6.8. The attack vector is local, with low attack complexity, low privileges required, and no user interaction. If exploited, it can affect confidentiality, integrity, and availability at a high level. Microsoft lists the exploit status as not publicly disclosed, not exploited, and exploit code maturity as unproven. Because it is local-only rather than network-exploitable, enterprise risk is higher on systems where attackers can obtain local code execution or shell access, but it is not an internet-facing remote attack.

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 with HIGH confidentiality, HIGH integrity, and HIGH availability impacts.
- Exploitation likelihood: Exploitation Less Likely; local attack vector with LOW attack complexity, LOW privileges required, and NO user interaction.
- Severity for enterprise: High technical severity, but risk is mainly on systems where local access is possible; lower exposure than network-based vulnerabilities.
- 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