CVE-2026-62880 Overview
CVE-2026-62880 is an out-of-bounds read vulnerability in the Windows New Technology File System (NTFS) driver. An authorized local attacker can leverage the flaw to elevate privileges on affected systems. The issue is tracked under CWE-125 and impacts a broad range of Windows client and server releases, from Windows 10 1607 through Windows Server 2025.
Microsoft published the advisory in the Microsoft Security Update Guide. Exploitation requires local access and low privileges, with no user interaction.
Critical Impact
Successful exploitation grants elevated privileges on the local host, enabling attackers to compromise confidentiality, integrity, and availability of the operating system.
Affected Products
- Microsoft Windows 10 (versions 1607, 1809, 21H2, 22H2)
- Microsoft Windows 11 (versions 23H2, 24H2, 25H2, 26H1)
- Microsoft Windows Server 2012, 2012 R2, 2016, 2019, 2022, and 2025
Discovery Timeline
- 2026-08-11 - CVE-2026-62880 published to NVD
- 2026-08-13 - Last updated in NVD database
Technical Details for CVE-2026-62880
Vulnerability Analysis
The vulnerability resides in the Windows NTFS driver, which manages on-disk file system metadata and structures. An out-of-bounds read [CWE-125] occurs when the driver processes attacker-controlled NTFS data and reads memory beyond an allocated buffer. The condition can be reached by an authorized user with the ability to mount, attach, or interact with a crafted NTFS volume or file structure.
Successful exploitation results in local privilege escalation. Attackers gain the ability to execute code with kernel-level privileges, giving full control over the affected host.
The EPSS probability places this issue in the lower tier of near-term exploitation likelihood, but the broad set of affected Windows versions widens the attack surface significantly.
Root Cause
The root cause is missing or insufficient bounds validation on data structures parsed by the NTFS driver. When the driver dereferences a length or offset value derived from untrusted metadata, it reads past the intended buffer boundary. The disclosed memory can contain sensitive kernel data such as pointers, tokens, or object headers that assist in bypassing exploit mitigations.
Attack Vector
Exploitation requires local access with low privileges and no user interaction. A typical attack chain involves an authenticated user attaching a malicious NTFS volume, virtual hard disk (VHD/VHDX), or file image. When the NTFS driver parses the crafted structures, the out-of-bounds read leaks kernel memory that the attacker uses to construct a follow-on primitive for privilege escalation. Verified public proof-of-concept code is not currently available.
The vulnerability is described in prose because no validated exploit code has been released. See the Microsoft Security Update Guide for vendor-supplied technical details.
Detection Methods for CVE-2026-62880
Indicators of Compromise
- Unexpected mounting or attachment of VHD, VHDX, or ISO images by non-administrative users.
- Kernel bugchecks or NTFS driver crashes (ntfs.sys) following user-initiated file system operations.
- New processes running with SYSTEM or elevated tokens that were launched from standard user sessions.
- Creation of scheduled tasks, services, or drivers immediately after suspicious file system activity.
Detection Strategies
- Monitor Windows event logs for driver faults referencing ntfs.sys and correlate with user session activity.
- Alert on non-administrative accounts invoking Mount-DiskImage, Mount-VHD, or PowerShell cmdlets that attach disk images.
- Track token elevation events (Event ID 4672) that follow file system driver anomalies.
- Baseline normal NTFS driver behavior and flag deviations such as repeated read faults from the same process.
Monitoring Recommendations
- Enable kernel-mode crash dump collection and retain dumps for post-incident review of NTFS faults.
- Ingest Windows Security, System, and Sysmon telemetry into a centralized data lake for cross-host correlation.
- Deploy endpoint behavioral monitoring capable of detecting local privilege escalation patterns.
- Restrict which users can attach removable media or virtual disks through Group Policy and audit those events.
How to Mitigate CVE-2026-62880
Immediate Actions Required
- Apply the Microsoft security update referenced in the Microsoft Security Update Guide to all affected Windows client and server systems.
- Prioritize patching on multi-user systems, terminal servers, and hosts where untrusted users can log in interactively.
- Audit accounts with local logon rights and remove unnecessary interactive access.
- Restrict the ability to mount arbitrary disk images to administrators only.
Patch Information
Microsoft has released cumulative updates addressing CVE-2026-62880 across all supported Windows versions listed in the advisory. Administrators should consult the Microsoft Security Update Guide for the specific KB article corresponding to each Windows build and deploy through Windows Update, WSUS, Intune, or Configuration Manager.
Workarounds
- Limit interactive logon on high-value systems until patches are deployed.
- Block standard users from mounting VHD, VHDX, and ISO files using Group Policy and file association restrictions.
- Enable AppLocker or Windows Defender Application Control to constrain unauthorized tooling that could stage exploitation.
- Increase monitoring of file system driver telemetry on unpatched hosts pending remediation.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
