Severity by source
AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Local-only race condition (AV:L, AC:H) exploitable by an authenticated low-privileged user (PR:L) with no interaction, yielding full local compromise (C:H/I:H/A:H, unchanged scope).
Primary rating from Vendor (microsoft).
CVSS VectorNVD
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
5DescriptionNVD
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Runtime allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Windows Runtime (WinRT) component of Windows 11 (24H2, 25H2, 26H1) and Windows Server 2022/2025 lets an already-authenticated local user race a shared resource to gain higher privileges. Microsoft (the reporting vendor) has shipped fixes; there is no public exploit identified at time of analysis and CISA SSVC rates exploitation as none, though the technical impact is total. EPSS is low at 0.24% (16th percentile), consistent with a high-complexity local flaw rather than a mass-exploited network bug.
Technical ContextAI
The flaw lives in the Windows Runtime (WinRT), the object-oriented API layer that underpins modern Windows app and system components across desktop and server SKUs. The root cause is CWE-362, concurrent execution using a shared resource with improper synchronization - a classic race condition (TOCTOU-style window) where two threads or contexts access the same object without adequate locking. An attacker who can execute code as a low-privileged local user times operations to hit the unsynchronized window, corrupting or substituting a shared object at the moment a higher-privileged path uses it, thereby crossing a security boundary. The affected CPEs are all Microsoft OS platforms: Windows 11 versions 24H2/25H2/26H1, Windows Server 2022, and Windows Server 2025 including the Server Core installation.
RemediationAI
Vendor-released patch: apply the Microsoft security updates that raise builds to at least 10.0.26100.8875 (Windows 11 24H2/25H2), 10.0.28000.2525 (Windows 11 26H1), 10.0.20348.5386 (Windows Server 2022), and 10.0.26100.33158 (Windows Server 2025 and Server Core) as documented at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58527. Deploy through your normal Windows Update / WSUS / Intune channel and reboot to complete servicing. No vendor workaround is published; because exploitation requires local code execution as a low-privileged user, the most effective compensating control until patching is to limit interactive and local logon rights to trusted accounts and enforce least privilege (removing standard users' ability to run arbitrary code reduces the pool of attackers who could attempt the race), with the trade-off that this does not neutralize the flaw and offers no protection where untrusted code already runs (e.g., multi-user or terminal-server hosts).
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Same weakness CWE-362 – Race Condition
View allSame technique Race Condition
View allShare
External POC / Exploit Code
Leaving vuln.today
EUVD-2026-44283
GHSA-pw8f-4h65-p7v4