CVE-2026-49798 is a Windows Kernel elevation of privilege vulnerability caused by a use-after-free condition. Microsoft rates it Critical with a CVSS v3.1 base score of 9.3 and temporal score of 8.1. The vector is local-only, requires no privileges and no user interaction, and has changed scope. If successfully exploited, an attacker could gain SYSTEM privileges. Microsoft indicates no public disclosure and no known exploitation, but rates exploitation as more likely. Because this is a local attack, it is less exposed than a network-reachable flaw, but it remains high risk for enterprise endpoints and servers where untrusted local code can run.

Highlights:
- CVSS scores: Base 9.3 - Temporal 8.1
- Exploit status & code maturity: Publicly Disclosed: No; Exploited: No; Exploit Code Maturity: UNPROVEN.
- Impact: Elevation of Privilege; confidentiality HIGH, integrity HIGH, availability HIGH.
- Exploitation likelihood: Exploitation More Likely; local vector with LOW attack complexity, NO privileges required, and NO user interaction.
- Severity for enterprise: High priority for Windows systems, especially hosts where local code execution is possible. The local-only vector lowers exposure compared with network-based vulnerabilities, but successful exploitation can lead to SYSTEM-level compromise.
- Patch status: available

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