Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local vector and low existing privileges required for a kernel UAF (AV:L/PR:L), no user interaction, and full SYSTEM compromise gives C/I/A High.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Use after free 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 gain SYSTEM-level control by exploiting a use-after-free (CWE-416) memory corruption condition. The flaw affects a broad range of supported Windows client and server releases (Windows 10 1809 through Windows 11 26H1, and Windows Server 2019 through 2025) and, per the CVSS 7.8 vector, yields full confidentiality, integrity, and availability impact. No public exploit identified at time of analysis, and the issue is not listed in CISA KEV; Microsoft has released a patch.
Technical ContextAI
The vulnerability resides in the Windows Kernel (ntoskrnl), the privileged core that mediates memory, scheduling, and object management for the entire OS. CWE-416 (Use After Free) means a kernel object is freed while a pointer to it remains in use; a subsequent dereference of that dangling pointer lets an attacker who can groom the freed allocation reclaim it with attacker-controlled data, corrupting kernel memory and pivoting to arbitrary read/write or control-flow hijack in ring 0. The affected CPE set spans Microsoft's currently-serviced Windows 10/11 branches and Windows Server 2019/2022/2025 (including Server Core installations), indicating the vulnerable code path is in a shared kernel component present across the entire modern Windows lineage. Tags additionally flag a Denial Of Service dimension, consistent with a UAF that can crash the kernel (bugcheck) if exploitation is unreliable.
RemediationAI
Apply the Microsoft security update for CVE-2026-50329 as delivered through Windows Update / WSUS / the MSRC update guide; Patch available per vendor advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50329 - consult that page for the exact patched KB build number matching each Windows 10/11 or Windows Server 2019/2022/2025 SKU, as the fixed build differs per release. Because the input does not include a single cross-SKU fix version string, install the KB corresponding to your specific OS build rather than a generic version number. As compensating controls until patching completes, reduce the population of untrusted local code: restrict interactive and RDP logon rights on servers to trusted administrators, enforce application allow-listing (WDAC/AppLocker) to block attacker-supplied binaries that would trigger the kernel path, and enable virtualization-based security / HVCI where supported to raise the bar on kernel exploitation - noting HVCI can affect unsigned drivers and legacy software compatibility. These controls limit who can reach the vulnerable code but do not remove the flaw, so patching remains the only complete fix.
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Same weakness CWE-416 – Use After Free
View allSame technique Use After Free
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-43852
GHSA-hgwq-93c2-v862