# CVE-2026-20936: Microsoft Windows NDIS out-of-bounds read

Source: https://junglewise.ai/threats/cve-2026-20936-microsoft-windows-ndis-out-of-bounds-read  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-01-13. Updated: 2026-07-30  
License: CC BY 4.0 with a link back

CVE-2026-20936 · Severity: medium · CVSS 4.3 · Published 2026-01-13

A security vulnerability exists in the Windows Network Driver Interface Specification (NDIS), a critical component that manages how the operating system communicates with network hardware. An attacker with physical access to a device and basic user credentials could exploit this flaw to view sensitive information stored in the system's memory. While the risk is mitigated by the requirement for physical proximity, it could lead to the unauthorized disclosure of private data.

Technologies: [Microsoft Windows 11](https://junglewise.ai/threats/technologies/windows-11), [Microsoft Windows Server 2008 R2](https://junglewise.ai/threats/technologies/windows-server-2008-r2), [Microsoft Windows 10](https://junglewise.ai/threats/technologies/windows-10). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-20936 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-20936 being exploited in the wild.

**How severe is CVE-2026-20936?** Medium severity, with a CVSS score of 4.3, published 13 January 2026.

**Which products and versions are affected?** Microsoft Windows 11 22H3, 23H2, 24H2, 25H2; Microsoft Windows Server 2008 R2 Service Pack 1; Microsoft Windows 10 1607, 1809, 21H2, 22H2.

**Is there a fix for CVE-2026-20936?** 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-2026-20936 attacked?** It is attacked with physical access, in an operating system.

**Am I affected by CVE-2026-20936?** Check whether you run Microsoft Windows 11, Microsoft Windows Server 2008 R2 or Microsoft Windows 10 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

An out-of-bounds read vulnerability (CWE-125) exists in the Microsoft Windows Network Driver Interface Specification (NDIS). The flaw is triggered when the component improperly handles memory buffers during network operations. An attacker must have physical access to the target machine and possess valid low-privileged credentials to exploit this vulnerability. Successful exploitation allows the attacker to read data from memory locations outside of the intended buffer, potentially leading to the disclosure of sensitive kernel or system information. Microsoft has released security updates to address this issue across affected Windows and Windows Server versions.

## Affected products

- Microsoft Windows 10 1607, 1809, 21H2, 22H2
- Microsoft Windows 11 22H3, 23H2, 24H2, 25H2
- Microsoft Windows Server 2008 R2 Service Pack 1

## Timeline

- 2026-01-13: disclosed
- 2026-01-13: advisory

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20936](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20936)

## Related threats

- [Microsoft Windows Recovery Environment UEFI/BIOS password bypass](https://junglewise.ai/threats/cve-2026-116638-the-windows-recovery-environment-winre-in-windows-10-and-11-may)
- [Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.](https://junglewise.ai/threats/cve-2026-68820-microsoft-windows-ancillary-function-driver-for-winsock-use-after)
- [Microsoft Windows Backup Engine privilege escalation](https://junglewise.ai/threats/cve-2026-58598-microsoft-windows-backup-engine-privilege-escalation)
- [Microsoft Windows Boot Loader security feature bypass](https://junglewise.ai/threats/cve-2026-58638-microsoft-windows-boot-loader-security-feature-bypass)
- [Microsoft Windows Client-Side Caching Service privilege escalation](https://junglewise.ai/threats/cve-2026-58637-microsoft-windows-client-side-caching-service-privilege)