EUVD-2026-44143
GHSA-4pvm-wg2g-h8cw
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local authenticated user (AV:L/PR:L) triggers a low-complexity kernel UAF with no user interaction, yielding SYSTEM-level total impact across C/I/A.
Primary rating from Vendor (microsoft).
CVSS VectorNVD
Lifecycle Timeline
5DescriptionNVD
Use after free in Windows Kernel allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Microsoft Windows Kernel affects Windows 11 (24H2, 25H2, 26H1) and Windows Server 2025, where a use-after-free memory-corruption flaw lets an already-authenticated local user execute code with SYSTEM-level privileges. No public exploit identified at time of analysis, and CISA SSVC records exploitation as none; the low EPSS score (0.32%, 24th percentile) reflects the absence of observed exploitation, though the total technical impact makes it a valuable second-stage escalation primitive. Reported by Microsoft with a vendor patch available.
Technical ContextAI
The vulnerability resides in the Windows Kernel (ntoskrnl-level code), the privileged core of the operating system that mediates memory management, scheduling, and object handling for all user-mode processes. The root cause is CWE-416 (Use After Free): kernel code continues to reference a memory object after it has been freed, allowing an attacker who controls subsequent allocations to reoccupy that freed region and manipulate kernel state. Because the kernel executes in ring 0, corrupting one of its objects can be leveraged to overwrite function pointers or object metadata and redirect execution or elevate the caller's token. The CPE data scopes this to Microsoft Windows 11 versions 24H2, 25H2, and 26H1, plus Windows Server 2025 including the Server Core installation, indicating the affected code path exists in the current Windows kernel build lineage rather than legacy releases.
RemediationAI
Vendor-released patch: apply the Microsoft cumulative update that raises the build to at least 10.0.26100.8875 for Windows 11 24H2, 10.0.26200.8875 for 25H2, 10.0.28000.2269 for 26H1, and 10.0.26100.33158 for Windows Server 2025 (including Server Core), as specified in the EUVD fixed-version data and the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50687. Because exploitation requires an authenticated local session, the most effective compensating control while patching is deploying via managed update rings, prioritizing multi-user, terminal-server, and shared-workstation hosts where untrusted users obtain interactive logons; on such systems, tighten local logon rights and remove unnecessary interactive user accounts to shrink the pool of potential attackers, accepting the trade-off that this restricts legitimate shared use. No standalone workaround (feature toggle or port block) is applicable to a kernel memory-corruption bug, so patching is the definitive fix.
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Same weakness CWE-416 – Use After Free
View allSame technique Denial Of Service
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External POC / Exploit Code
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