Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local kernel UAF triggerable by a standard user with no interaction (AV:L/AC:L/PR:L/UI:N), yielding SYSTEM-level control so C/I/A all High, scope unchanged.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Use after free in Windows Cloud Files Mini Filter Driver allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Windows Cloud Files Mini Filter Driver (cldflt.sys) lets an authenticated low-privileged user corrupt kernel memory to gain SYSTEM-level control. The flaw is a use-after-free (CWE-416) affecting a broad range of Windows client and server builds from Windows 10 1809 through Windows 11 26H1 and Windows Server 2019-2025. Microsoft has released a patch; there is no public exploit identified at time of analysis and it is not listed in CISA KEV.
Technical ContextAI
The affected component is the Windows Cloud Files Mini Filter Driver (cldflt.sys), the kernel-mode file-system mini-filter that backs the Cloud Files API / 'Files On-Demand' placeholder mechanism used by OneDrive and other cloud sync providers to present remote files as local placeholders. As a filter driver it runs in ring 0 and intercepts file I/O, so a memory-safety defect here executes in kernel context. The root cause is CWE-416 (Use After Free): the driver continues to reference an object after it has been freed, allowing an attacker who can reclaim and control the freed allocation to influence kernel execution or corrupt kernel data structures. The CPE set indicates the defect is present across the shared Windows codebase spanning Windows 10 1809/21H2/22H2, Windows 11 24H2/25H2/26H1, and Windows Server 2019/2022/2025 (including Server Core installations).
RemediationAI
Apply the Microsoft security update for CVE-2026-58613 (Vendor-released patch: available per Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58613) via Windows Update or WSUS/SCCM for each affected SKU; consult the MSRC update guide for the exact KB and fixed build for your specific version. No official pre-patch workaround was provided by the vendor; because the flaw is in the Cloud Files mini-filter that underpins OneDrive Files On-Demand, environments that do not use cloud file placeholders can reduce exposure by disabling OneDrive Files On-Demand / cloud sync where operationally acceptable, at the cost of losing on-demand file functionality, and should enforce least-privilege so untrusted users cannot run code locally (this raises the bar since exploitation requires local low-privileged access but does not eliminate the risk). Patching is the only confirmed remediation and should be prioritized on multi-user and shared hosts.
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Same weakness CWE-416 – Use After Free
View allSame technique Use After Free
View allShare
External POC / Exploit Code
Leaving vuln.today
EUVD-2026-44304
GHSA-9f2j-4qc4-329w