Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local low-privileged access with no user interaction and no complexity barrier yields full SYSTEM compromise, so AV:L/PR:L/AC:L with C/I/A all High and unchanged scope.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Improper access control in Windows Kernel allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Microsoft Windows Kernel allows an already-authenticated attacker to elevate to SYSTEM-level privileges across a wide range of Windows 10, Windows 11, and Windows Server builds. The flaw stems from improper access control (CWE-284) in kernel-mode code and requires local low-privileged access with no user interaction. There is no public exploit identified at time of analysis and it is not listed in CISA KEV, but the trivial attack complexity and SYSTEM-level impact make it a standard patch-Tuesday priority.
Technical ContextAI
The vulnerability resides in the Windows Kernel (ntoskrnl), the core ring-0 component that mediates access to processes, memory, tokens, and system objects. CWE-284 (Improper Access Control) indicates the kernel fails to correctly enforce authorization boundaries on a securable object or operation, letting a low-privileged process perform actions reserved for higher-privileged contexts. The CPE data confirms the affected surface is the base OS kernel shipped in Windows 10 21H2/22H2, Windows 11 24H2/25H2/26H1, and Windows Server 2022/2025 (including Server Core), meaning the defective code path is present in the common kernel image across both client and server SKUs rather than an optional feature or add-on component.
RemediationAI
Patch available per vendor advisory: apply the Microsoft security update for CVE-2026-50423 published in the MSRC Update Guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50423, selecting the KB matching each affected build (Windows 10 21H2/22H2, Windows 11 24H2/25H2/26H1, Windows Server 2022/2025 and Server Core). Because exploitation requires an existing local low-privileged session, interim compensating controls focus on limiting who can run code on the host: enforce least-privilege on interactive and service accounts, restrict local logon rights, and apply application allow-listing (WDAC/AppLocker) to block untrusted binaries that would deliver the exploit - these reduce the pool of potential local attackers but do not remediate the kernel flaw and can impact legitimate software deployment, so patching remains the only real fix. No kernel-level configuration workaround is documented in the available data.
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Same weakness CWE-284 – Improper Access Control
View allSame technique Authentication Bypass
View allShare
External POC / Exploit Code
Leaving vuln.today
EUVD-2026-43924
GHSA-8m88-gc88-rm4v