EUVD-2026-29582
GHSA-w4v7-8hgj-37j2
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local-only kernel EoP requiring an existing low-privileged session (AV:L, PR:L, AC:L, UI:N); successful exploitation yields SYSTEM, giving total C/I/A impact.
Primary rating from NVD.
CVSS VectorNVD
Lifecycle Timeline
2DescriptionCVE.org
Use after free in Windows Cloud Files Mini Filter Driver allows an authorized attacker to elevate privileges locally.
Articles & Coverage 1
AnalysisAI
Local privilege escalation in the Windows Cloud Files Mini Filter Driver (cldflt.sys) allows an authenticated low-privileged user to elevate to SYSTEM by triggering a use-after-free memory-corruption condition. The flaw was reported by Microsoft and affects a broad range of Windows 10, Windows 11, and Windows Server builds; a vendor patch is available. There is no public exploit identified at time of analysis, and EPSS exploitation probability is very low (0.06%).
Technical ContextAI
The affected component is the Windows Cloud Files Mini Filter Driver (commonly cldflt.sys), a kernel-mode filter driver that underpins the Cloud Files API / 'Files On-Demand' placeholder functionality used by OneDrive and other cloud sync providers to present remote files as local placeholders. The CPE data confirms the affected surface spans desktop editions (Windows 10 1809/21H2/22H2, Windows 11 22H3/23H2/24H2/25H2/26H1) and server editions (Server 2019/2022/2025 including Server Core). The root cause is CWE-416 (Use After Free): the driver continues to reference kernel memory after it has been freed, allowing an attacker to reclaim and control that memory to corrupt kernel state and hijack execution flow in ring 0.
RemediationAI
Vendor-released patch: apply the Microsoft cumulative security update that brings each edition to or above its fixed build listed above (e.g., 10.0.26100.8457 for Windows 11 24H2, 10.0.17763.8755 for Windows 10 1809 / Server 2019). Deploy via Windows Update / WSUS / your patch-management pipeline as part of the standard monthly cycle, prioritizing multi-user and shared systems where untrusted local accounts exist. The vendor guidance is at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33835. As a compensating control where patching must be deferred, restrict interactive/local logon to trusted accounts and reduce the number of low-privileged local users, since exploitation requires local code execution; where the Cloud Files feature is unused, disabling OneDrive Files On-Demand / cloud placeholder sync reduces reachable driver code paths, at the trade-off of losing on-demand file functionality. There is no reliable network-layer mitigation because this is a local-only EoP.
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Same weakness CWE-416 – Use After Free
View allSame technique Denial Of Service
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External POC / Exploit Code
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