Windows Bind Filter EUVD-2026-56358

Exploitation requires local authenticated access to the target system with at minimum a standard (low-privilege) user account, reflected in the CVSS vector as AV:L and PR:L. No interaction from a second user is required (UI:N), and attack complexity is low (AC:L), meaning no race condition, specific non-default configuration, or environmental prerequisite has been identified beyond having a valid local logon session. Exploitation is bounded to Windows 11 versions 24H2, 25H2, and 26H1 and Windows Server 2025 (including Server Core) that have not been updated to the corrected build versions. Remote unauthenticated exploitation is excluded by the local attack vector. Earlier Windows versions are not listed as affected in the available intelligence data.

The CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) characterizes this as a local privilege escalation with low complexity and no user interaction required beyond a standard user account, yielding full confidentiality, integrity, and availability impact. The local attack vector constrains mass exploitation but is highly relevant in post-phishing scenarios, shared multi-user environments, and cloud virtual machines where initial access via low-privilege accounts is a common attacker foothold. EPSS data was not provided in the intelligence package, leaving probabilistic exploitation likelihood unquantified; however, the AC:L rating suggests exploitation is not technically demanding once local access is established. The vulnerability is not listed in CISA KEV and no public exploit has been identified, meaning real-world exploitation pressure is unconfirmed at this time. Despite these moderating factors, even a mid-sized municipal IT team in swidnica managing mixed Windows 11 and Windows Server 2025 fleets should treat this as an urgent patching priority, since local privilege escalation flaws are frequently chained with initial-access techniques in ransomware and advanced persistent threat campaigns. The absence of EPSS data and KEV listing represents a gap in this assessment.

An attacker who has established a foothold on a target Windows 11 or Windows Server 2025 system through phishing, credential theft, or chained vulnerability exploitation uses a low-privilege local account to interact with the Windows Bind Filter Driver in a manner that triggers the heap-based buffer overflow. By supplying crafted input that overflows the vulnerable heap allocation, the attacker corrupts kernel memory structures and redirects execution to attacker-controlled code, escalating from a standard user to SYSTEM. No public exploit code has been identified at time of analysis, but the low attack complexity (AC:L) indicates exploitation does not rely on timing, race conditions, or specialized environmental knowledge.