# CVE-2026-83864: Windows NTFS improper access control information disclosure

Source: https://junglewise.ai/threats/cve-2026-83864-improper-access-control-in-windows-ntfs-allows-an-authorized  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-83864 · Severity: medium · CVSS 5.5 · Published 2026-10-13

Windows NTFS, the file system that stores all data on Windows computers, has an access control flaw that allows an authorized user to read files they should not have permission to access. An attacker with legitimate user credentials could exploit this to steal sensitive information stored on the system, including documents, emails, or configuration files containing passwords or other secrets.

Technologies: [Microsoft Windows NTFS](https://junglewise.ai/threats/technologies/windows-ntfs). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-83864 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-83864 being exploited in the wild.

**How severe is CVE-2026-83864?** Medium severity, with a CVSS score of 5.5, published 13 October 2026.

**Which products and versions are affected?** Microsoft Windows NTFS.

**Is there a fix for CVE-2026-83864?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-83864 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-83864?** Check whether you run Microsoft Windows NTFS. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An improper access control vulnerability in Windows NTFS permits an authenticated attacker to bypass file access restrictions and disclose sensitive information through local access. The vulnerability requires existing user credentials but does not require additional user interaction. Mitigation requires a security patch from Microsoft.

## Affected products

- Microsoft Windows NTFS

## Timeline

- 2026-10-13: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83864](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83864)

## Related threats

- [Windows NTFS pointer dereference remote code execution](https://junglewise.ai/threats/cve-2026-105542-untrusted-pointer-dereference-in-windows-ntfs-allows-an)
- [Windows NTFS format string privilege elevation](https://junglewise.ai/threats/cve-2026-83585-use-of-externally-controlled-format-string-in-windows-ntfs-allows)
- [Windows NTFS out-of-bounds read privilege escalation](https://junglewise.ai/threats/cve-2026-83508-out-of-bounds-read-in-windows-ntfs-allows-an-authorized-attacker)
- [Windows NTFS integer overflow allows privilege escalation](https://junglewise.ai/threats/cve-2026-69916-integer-overflow-or-wraparound-in-windows-ntfs-allows-an)
- [Microsoft Windows NTFS out-of-bounds read privilege escalation](https://junglewise.ai/threats/cve-2026-77503-microsoft-windows-ntfs-out-of-bounds-read-privilege-escalation)