Windows Container Isolation CVE-2026-97792

Exploitation requires the attacker to already have authenticated, low-privileged code-execution access on the target host (PR:L, AV:L) - it is not remotely reachable and cannot be used for initial compromise. The specific prerequisite is the presence and activation of the Windows Container Isolation FS Filter Driver (unionfs.sys), which underpins Windows container/filesystem-isolation features; the attacker must be able to interact with this driver locally. Limiting factors: local access is mandatory, the target must be an unpatched build within the affected ranges (e.g. Windows 11 24H2 <10.0.26100.9711, Windows Server 2025 <10.0.26100.33650, Windows Server 2022 <10.0.20348.5761), and no network or remote vector exists.

This is a credible but second-tier priority for most environments. The CVSS vector (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, 7.8 HIGH) describes a classic local privilege-escalation chain: an attacker who already holds some foothold (PR:L) on the host can, with low attack complexity and no user interaction, elevate to full SYSTEM/kernel privileges (C:H/I:H/A:H). The CWE-732 (incorrect permission assignment) classification is consistent with the 'improper access control' description in the unionfs.sys container-isolation filter driver. Critically, there is no EPSS score, no CISA KEV listing, and no public POC in the supplied data, so there are no signals of active or imminent mass exploitation - this is not an internet-facing, auto-exploitable flaw. The AV:L requirement means it cannot be used for initial access; it is a post-compromise escalation primitive. One data-quality conflict stands out: the input Tags label this 'Information Disclosure,' but both the description ('elevate privileges locally') and the full-impact CVSS triad indicate an Elevation-of-Privilege bug, not information disclosure - treat the tag as mislabeled. Microsoft (the reporting party) has shipped a patch, which is the primary mitigation.

An attacker who has already gained low-privileged code execution on a Windows host - for example via phishing, a compromised service account, or a container escape attempt - invokes the vulnerable Container Isolation FS filter driver (unionfs.sys) to abuse its improper access-control checks and elevate to SYSTEM. No user interaction is required and attack complexity is low. No public exploit code was identified at time of analysis, so weaponization would require independent exploit development.