Windows Cloud Files CVE-2026-33835

Exploitation requires the attacker to already possess local, authenticated access with at least low privileges (CVSS PR:L) and the ability to execute code on the target host; there is no remote or network path (AV:L) and no user interaction (UI:N). The specific trigger is the Cloud Files Mini Filter Driver code path (cldflt.sys), which is present and loaded by default on the affected Windows builds to support cloud file placeholders/Files On-Demand - so on default installations the vulnerable driver surface is reachable. Limiting factors: the attacker cannot start from zero (must already have a local user session/code execution), SSVC rates exploitation 'none' and automatable 'no,' and only builds below the fixed versions listed are affected.

The CVSS 3.1 vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H yields a base score of 7.8 (High): local attack vector, low complexity, low privileges required, no user interaction, and total (High/High/High) impact on confidentiality, integrity, and availability - consistent with a SYSTEM-level EoP. This aligns with the SSVC framework, which rates Technical Impact as 'total.' However, the risk-priority signals are mixed toward lower urgency: SSVC lists Exploitation as 'none' and Automatable as 'no,' EPSS is only 0.06% (18th percentile), and the vulnerability is not on CISA KEV. This is a genuine kernel EoP but currently reflects a patch-in-normal-cycle priority rather than an emergency, because it requires pre-existing local code execution and there is no evidence of exploitation or automatable mass abuse. Note a minor inconsistency: input tags list 'Denial Of Service,' but the CVSS/CWE and 'authorized attacker to elevate privileges' language point to privilege escalation as the primary impact - treat DoS as a secondary/possible outcome.

An attacker who already has a low-privileged foothold on a Windows host - for example via a compromised standard user account or a sandboxed application - runs a crafted program that drives the Cloud Files mini filter driver into a use-after-free state, reclaims the freed kernel object, and corrupts kernel memory to execute code as SYSTEM. No user interaction is required. No public exploit code has been identified at time of analysis, so this reflects a plausible but not-yet-demonstrated attack path.