CVE-2026-50436 is a Windows Kernel use-after-free vulnerability that can be exploited for elevation of privilege to SYSTEM. Microsoft rates it as High severity with a CVSS v3.1 base score of 7.8 and temporal score of 6.8; the vector is local access, low attack complexity, low privileges required, no user interaction, and unchanged scope. Microsoft says it is not publicly disclosed and not exploited, with exploit code maturity marked UNPROVEN. Because the attack is local-only, the main enterprise risk is on systems where an attacker can already obtain local 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. Microsoft says successful exploitation could grant SYSTEM privileges.
- Exploitation likelihood: Exploitation More Likely; vector context is LOCAL with LOW attack complexity, LOW privileges required, and NO user interaction.
- Severity for enterprise: High technical severity, but lower enterprise exposure than network-reachable issues because exploitation requires local access. Risk is most relevant on endpoints or servers where untrusted local code or users can run.
- Patch status: available; customer action required.

Affected systems:
- Windows 11 24H2
- Windows 11 25H2
- Windows 11 26H1
- Windows 11 unspecified
- Windows Server 2025