CVE-2026-50489 is a Win32k heap-based buffer overflow that allows elevation of privilege to SYSTEM. Microsoft rates it as HIGH severity with a CVSS v3.1 base score of 8.8 and temporal score of 7.7. The vector is local attack only, with low attack complexity, low privileges required, no user interaction, and changed scope. Microsoft says it has not been publicly disclosed or exploited, but rates exploitation as more likely. Because it is a local privilege escalation issue, the main enterprise risk is on systems where attackers can already obtain local execution or low-privilege access.

Highlights:
- CVSS scores: Base 8.8 - Temporal 7.7
- Exploit status & code maturity: Publicly Disclosed: No; Exploited: No; Exploit Code Maturity: UNPROVEN
- Impact: Elevation of Privilege; confidentiality, integrity, and availability impacts are HIGH
- Exploitation likelihood: Exploitation More Likely; local vector with LOW attack complexity, LOW privileges required, and NO user interaction
- Severity for enterprise: High. The attack is local-only, so it is less relevant to network-exposed services, but successful exploitation can lead to SYSTEM privileges on affected Windows hosts
- 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