Windows Kernel EUVD-2026-100056

Exploitation requires the attacker to already possess local, authenticated access with low privileges (PR:L) on the target Windows system - this is a privilege-escalation primitive, not a remote entry point (AV:L). No user interaction is required (UI:N). The key limiting factor is high attack complexity (AC:H): use-after-free exploitation in the Windows Kernel typically depends on winning a race condition or achieving a specific memory-reuse state that is not reliably under the attacker's control, reducing exploit reliability. Affected scope spans essentially all supported Windows client and server builds below the patched versions listed in EUVD-2026-100056 (e.g., Windows 11 24H2 before 10.0.26100.9711, Windows Server 2025 before 10.0.26100.33650), so a default, unpatched installation is vulnerable - there is no special feature or non-default configuration required beyond having a local account.

This is a legitimate but not top-tier priority. The CVSS 3.1 vector (AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H, base 7.0 HIGH) describes a locally exploitable Windows Kernel use-after-free requiring an already-authenticated low-privileged user and a high-complexity attack (AC:H), meaning the attacker must win a race or satisfy conditions not fully under their control. All three impact metrics are High, consistent with the SSVC 'Technical Impact: total' rating and the typical outcome of a successful kernel UAF (SYSTEM-level privilege escalation). Crucially, the non-CVSS exploitation signals point DOWN: SSVC records 'Exploitation: none' and 'Automatable: no', there is no CISA KEV listing and no public exploit identified at time of analysis. These signals are consistent rather than conflicting - a high technical impact but currently no evidence of exploitation and high attack complexity. The practical takeaway: patch it as part of normal Patch Tuesday cadence (vendor patch is available) because the affected footprint is enormous, but it is not an emergency drop-everything issue absent any exploitation or POC evidence. No EPSS score was provided in the input, so probabilistic exploitation likelihood could not be factored in.

An attacker who already has a low-privileged authenticated foothold on a Windows host (e.g., via phishing, a compromised standard user account, or a sandboxed process) runs a crafted local program that triggers the kernel use-after-free, winning a timing/race condition (AC:H) to corrupt kernel memory and escalate to SYSTEM. No public exploit is identified at time of analysis, and the high attack complexity means reliable weaponization is non-trivial.