EUVD-2026-44097
GHSA-qhx9-cjw7-mfcq
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local use-after-free EoP triggerable by an authenticated low-privileged user without interaction (AV:L, PR:L, UI:N), granting full SYSTEM-level control (C/I/A:H) within unchanged scope.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Use after free in Windows Runtime allows an authorized attacker to elevate privileges locally.
AnalysisAI
Elevation of privilege in the Windows Runtime (WinRT) component affects Windows 10 (21H2/22H2), Windows 11 (24H2/25H2/26H1), and Windows Server 2025, where a use-after-free memory-corruption flaw lets an already-authenticated local user run code at higher privilege. Microsoft has released a patch and reported the issue; there is no public exploit identified at time of analysis and the CVE is not listed in CISA KEV. Given the CVSS 7.8 (Important) rating and full C/I/A impact, this is a standard local privilege-escalation risk suited for regular patch prioritization rather than emergency response.
Technical ContextAI
The Windows Runtime (WinRT) is the modern API/object model that underpins Universal Windows Platform and many in-box Windows apps and services, exposing COM-based components consumed by low-privilege processes. The root cause is CWE-416 (Use After Free): an object is freed while a dangling reference remains, and subsequent access to that stale pointer allows an attacker to control freed heap memory, corrupt object state, and redirect execution or manipulate privileged data. Because WinRT components are invoked broadly across the OS, a UAF here provides a local attacker a reachable primitive from user-mode code. The affected CPEs enumerate Windows 10 Version 21H2 and 22H2, Windows 11 Version 24H2, 25H2 and 26H1, and Windows Server 2025 including Server Core, confirming a broad supported-OS impact.
RemediationAI
Patch available per vendor advisory - apply the Microsoft security update for CVE-2026-50486 referenced at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50486, selecting the cumulative update matching each affected build (Windows 10 21H2/22H2, Windows 11 24H2/25H2/26H1, and Windows Server 2025 including Server Core); exact fixed build numbers are listed in the MSRC update guide entry. No standalone workaround is published for a use-after-free in a core OS runtime, so the update is the authoritative fix; as compensating controls until patching, restrict and monitor local/interactive logon rights and enforce least privilege so fewer accounts can run the local code needed to trigger the flaw, and apply application allowlisting (e.g., WDAC/AppLocker) to reduce an attacker's ability to execute the initial low-privilege code - with the trade-off that these controls limit reachability but do not remediate the underlying bug.
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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