CVE-2026-62722: Windows 11 24H2 Privilege Escalation Flaw

CVE-2026-62722 Overview

CVE-2026-62722 is a heap-based buffer overflow in the Windows Bind Filter Driver (bindflt.sys). An authorized local attacker can trigger the flaw to elevate privileges on affected Windows 11 and Windows Server 2025 systems. The weakness is categorized under CWE-122: Heap-based Buffer Overflow.

Successful exploitation grants the attacker SYSTEM-level code execution, breaking the boundary between standard user context and the Windows kernel. Microsoft published the advisory on August 11, 2026, and the issue affects Windows 11 24H2, 25H2, 26H1, and Windows Server 2025 across x64 and ARM64 builds.

Critical Impact
Local privilege escalation to SYSTEM through kernel-mode memory corruption in the Bind Filter Driver, enabling full compromise of the host.

Affected Products

Microsoft Windows 11 24H2 (x64, ARM64)
Microsoft Windows 11 25H2 (x64, ARM64)
Microsoft Windows 11 26H1 (x64, ARM64)
Microsoft Windows Server 2025 (x64)

Discovery Timeline

2026-08-11 - Microsoft releases security advisory for CVE-2026-62722
2026-08-11 - CVE-2026-62722 published to the National Vulnerability Database (NVD)
2026-08-13 - Last updated in NVD database

Technical Details for CVE-2026-62722

Vulnerability Analysis

The Windows Bind Filter Driver (bindflt.sys) is a kernel-mode filter driver that provides path-redirection functionality used by Windows containers, application isolation, and virtualization features. The driver operates as a mini-filter above the file system stack and processes user-controlled path and mapping data supplied through documented I/O control paths.

CVE-2026-62722 stems from insufficient bounds validation when the driver allocates and populates a heap buffer to store attacker-influenced input. When the input exceeds the calculated allocation size, adjacent pool memory is overwritten. Because bindflt.sys executes in kernel context, the overflow corrupts kernel pool structures rather than user-mode heap.

Root Cause

The root cause is a mismatch between the size used to allocate a pool buffer and the size of data subsequently copied into it. This classic [CWE-122] pattern permits a linear heap overflow inside the non-paged or paged pool used by bindflt.sys, enabling controlled overwrite of adjacent kernel objects.

Attack Vector

Exploitation requires local access and low-privileged authenticated execution. An attacker running arbitrary code as a standard user issues crafted requests to bindflt.sys to allocate an undersized pool chunk and then trigger the oversized copy. By grooming the pool to place a target object adjacent to the vulnerable allocation, the attacker overwrites function pointers or object headers to hijack control flow and execute code with SYSTEM privileges.

No public proof-of-concept has been released, and the vulnerability is not listed on the CISA Known Exploited Vulnerabilities catalog at the time of publication. Refer to the Microsoft CVE-2026-62722 Advisory for vendor-specific technical guidance.

// No verified public exploit code is available for CVE-2026-62722.
// The vulnerability is described in prose above; consult the Microsoft
// advisory for authoritative technical details.

Detection Methods for CVE-2026-62722

Indicators of Compromise

Unexpected loading or interaction with bindflt.sys from non-container, non-virtualization workloads.
Kernel bugchecks referencing bindflt.sys in MEMORY.DMP or Minidump files, particularly BAD_POOL_HEADER (0x19) or KERNEL_MODE_HEAP_CORRUPTION (0x13A).
Standard user processes spawning SYSTEM-level children (for example, cmd.exe or powershell.exe) shortly after issuing bind filter I/O.

Detection Strategies

Hunt for anomalous DeviceIoControl calls targeting the bind filter device from non-administrative processes.
Correlate Windows Error Reporting (WER) crash events for bindflt.sys with a preceding non-privileged process context.
Alert on integrity-level transitions where a Medium-integrity process elevates a child to System without a documented UAC or service path.

Monitoring Recommendations

Ingest Sysmon Event ID 1 (process creation) and Event ID 10 (process access) into a centralized data lake and pivot on parent-child integrity mismatches.
Track kernel crash telemetry and pool corruption bugchecks across the fleet to surface exploitation attempts that fail.
Baseline expected consumers of bindflt.sys (container runtimes, wslservice, application isolation) and alert on deviations.

How to Mitigate CVE-2026-62722

Immediate Actions Required

Apply the Microsoft security update referenced in the Microsoft CVE-2026-62722 Advisory to all affected Windows 11 24H2, 25H2, 26H1, and Windows Server 2025 systems.
Prioritize patching on multi-tenant hosts, developer workstations, and jump servers where low-privileged users have interactive access.
Restrict local logon and remote interactive sessions on servers that have not yet received the update.

Patch Information

Microsoft has issued cumulative security updates addressing CVE-2026-62722. Deploy the update through Windows Update, Windows Server Update Services (WSUS), Microsoft Intune, or your standard patch management pipeline. Validate installation by confirming the updated build number on each host after reboot.

Workarounds

No official workaround replaces the patch. If patching must be delayed, reduce risk by removing standard user local logon rights on critical hosts.
Where the bind filter is not required, avoid enabling Windows container features, Windows Subsystem for Linux, and application isolation workloads on unpatched systems.
Enforce application allow-listing to prevent unauthorized binaries from issuing I/O to bindflt.sys.

bash

# Verify installed KB and OS build on Windows after applying the update
Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 10
Get-ComputerInfo | Select-Object OsName, OsVersion, OsBuildNumber, WindowsVersion