# CVE-2026-81354: Microsoft Windows Hello heap buffer overflow

Source: https://junglewise.ai/threats/cve-2026-81354-microsoft-windows-hello-heap-buffer-overflow  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-08. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-81354 · Severity: high · CVSS 8.2 · Published 2026-09-08

Windows Hello is Microsoft's biometric authentication system used to unlock Windows devices. A heap buffer overflow in this component allows an authorized local attacker to escalate their privileges on the system, potentially gaining administrative access and full control of the device.

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

## Quick answers

**Is CVE-2026-81354 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-81354 being exploited in the wild.

**How severe is CVE-2026-81354?** High severity, with a CVSS score of 8.2, published 8 September 2026.

**Which products and versions are affected?** Microsoft Windows Hello unknown.

**Is there a fix for CVE-2026-81354?** 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-2026-81354 attacked?** It is attacked with local access.

**Am I affected by CVE-2026-81354?** Check whether you run Microsoft Windows Hello at an affected version. 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

A heap-based buffer overflow exists in Windows Hello's memory handling. The vulnerability requires the attacker to already have local access and be able to execute code on the system. By crafting a malicious input or triggering specific Windows Hello operations, an attacker can overflow a heap buffer and overwrite adjacent memory structures. This allows arbitrary code execution at a higher privilege level, enabling local privilege escalation to administrator or SYSTEM level.

## Affected products

- Microsoft Windows Hello unknown

## Timeline

- 2026-09-08: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-81354](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-81354)

## Related threats

- [Microsoft Windows Hello certificate validation bypass](https://junglewise.ai/threats/cve-2026-83926-improper-certificate-validation-in-windows-hello-allows-an)
- [Windows Hello use after free privilege escalation](https://junglewise.ai/threats/cve-2026-83853-use-after-free-in-windows-hello-allows-an-authorized-attacker-to)
- [Microsoft Windows Hello out-of-bounds read](https://junglewise.ai/threats/cve-2026-83849-out-of-bounds-read-in-windows-hello-allows-an-authorized-attacker)
- [Microsoft Windows Hello security feature bypass via uncontrolled search path](https://junglewise.ai/threats/cve-2026-72980-microsoft-windows-hello-security-feature-bypass-via-uncontrolled)
- [Microsoft Windows Hello use-after-free privilege escalation](https://junglewise.ai/threats/cve-2026-69864-microsoft-windows-hello-use-after-free-privilege-escalation)