Windows Cloud Files CVE-2026-88107

Exploitation requires the attacker to already have local, authenticated access to the Windows host (PR:L) and the ability to run code that drives Cloud Files / cloud-storage placeholder operations handled by the Cloud Files mini filter driver (cldflt.sys). Because the root cause is a race condition (CWE-362, reflected as AC:H), successful exploitation depends on winning a narrow timing window during concurrent file operations, which limits reliability and typically requires multiple attempts. No remote vector and no user interaction are involved; the limiting factors are the need for prior local foothold, valid (even low) privileges, and the inherent non-determinism of the race, substantially reducing realistic risk versus the raw score.

This is a locally-exploitable elevation-of-privilege flaw with a moderate CVSS 3.1 base score of 7.0 (AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H). The vector confirms it is NOT remotely exploitable: an attacker must already have local, authenticated code execution (PR:L) and must win a race condition (AC:H, consistent with CWE-362), which materially lowers reliability and real-world exploitability. All available exploitation signals point low: CISA SSVC lists Exploitation as 'none' and Automatable as 'no', and there is no CISA KEV listing and no public exploit identified at time of analysis - so this is NOT a currently-exploited priority. The one signal pulling upward is SSVC Technical Impact 'total', matching the C:H/I:H/A:H impact of a kernel-driver use-after-free that can yield SYSTEM. No EPSS score was provided in the input, so probabilistic exploitation likelihood could not be weighed. Net assessment: a real but second-tier patch-management priority - meaningful impact (kernel/SYSTEM via UAF) but gated behind local access, authentication, and a hard-to-win race, with no evidence of active or automatable exploitation. All signals are internally consistent; no conflict between the CVSS vector and the description (both indicate local, authorized access).

An attacker who already has a low-privileged authenticated foothold on a Windows host (e.g., via phishing or a compromised standard user account) runs a crafted local program that repeatedly manipulates Cloud Files (cloud sync/placeholder) operations to trigger a use-after-free race in the mini filter driver. By winning the timing window, they corrupt kernel memory to execute code at SYSTEM and fully compromise the machine. No public exploit was identified at time of analysis, and the high attack complexity (race condition) makes reliable exploitation non-trivial.