EUVD-2026-44127
GHSA-4qp5-vj95-jrvm
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local vector and low privileges required for an authenticated user (AV:L/PR:L), no user interaction, and Microsoft-asserted full C/I/A impact from a kernel EoP.
Primary rating from Vendor (microsoft).
CVSS VectorNVD
Lifecycle Timeline
5DescriptionNVD
Out-of-bounds read in Windows Kernel allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Windows Kernel affects a broad range of Windows 10, Windows 11, and Windows Server builds through an out-of-bounds read (CWE-125) that an already-authenticated attacker can leverage to gain higher privileges. Microsoft has released patches, but there is no public exploit identified at time of analysis and the EPSS probability is low (0.24%). CISA SSVC rates exploitation as none while noting total technical impact, indicating a serious-but-not-yet-exploited kernel flaw typical of Patch Tuesday servicing.
Technical ContextAI
The vulnerability resides in the Windows Kernel (ntoskrnl/kernel-mode components), the most privileged code in the OS that mediates memory, process, and hardware access. The root cause is an out-of-bounds read (CWE-125), where the kernel reads memory beyond the bounds of an allocated buffer - often due to missing or incorrect length validation on attacker-influenced input crossing the user-to-kernel boundary. Although classified as an out-of-bounds read (typically information disclosure, and tagged as such), Microsoft assigns full C/I/A impact, implying the leaked kernel data (e.g., pointers, tokens, or object addresses) can be used to defeat KASLR or corrupt kernel state and thereby elevate privileges. CPE data confirms the affected surface spans client and server SKUs from Windows 10 1809 through Windows 11 26H1 and Windows Server 2019 through 2025, including Server Core installations.
RemediationAI
Apply the Microsoft security update for CVE-2026-50670 via the MSRC Update Guide (https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50670); this is a vendor-released patch. Upgrade to at least the following build for each SKU: Windows 10 1809/Server 2019 to 10.0.17763.9020, Windows 10 21H2/22H2 to 10.0.19044.7548 / 10.0.19045.7548, Windows Server 2022 to 10.0.20348.5386, Windows 11 24H2 to 10.0.26100.8875, Windows Server 2025 to 10.0.26100.33158, Windows 11 25H2 to 10.0.26200.8875, and Windows 11 26H1 to 10.0.28000.2525. Because exploitation requires local authenticated access, interim compensating controls include restricting interactive and remote-interactive logon rights to trusted accounts, enforcing least privilege to reduce the pool of low-privileged local users, and monitoring for anomalous local process behavior; note these reduce but do not eliminate exposure since any low-privileged local user can attempt the flaw, so patching remains the only complete fix.
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External POC / Exploit Code
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