# CVE-2026-78445: Microsoft Windows Services for NFS use-after-free in ONCRPC XDR driver

Source: https://junglewise.ai/threats/cve-2026-78445-microsoft-windows-services-for-nfs-use-after-free-in-oncrpc-xdr  
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-2026-78445 · Severity: critical · CVSS 9.8 · Published 2026-09-08

Windows Services for NFS is a network component that allows Windows systems to access files on Unix/Linux servers. A use-after-free vulnerability in the ONCRPC XDR driver allows an attacker to execute arbitrary code remotely on affected systems without authentication, potentially giving them full control over the machine and access to all corporate data.

Technologies: [Microsoft Windows Services for NFS](https://junglewise.ai/threats/technologies/windows-services-for-nfs). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-78445 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-78445 being exploited in the wild.

**How severe is CVE-2026-78445?** Critical severity, with a CVSS score of 9.8, published 8 September 2026.

**Which products and versions are affected?** Microsoft Windows Services for NFS.

**Is there a fix for CVE-2026-78445?** 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-2026-78445 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-78445?** Check whether you run Microsoft Windows Services for NFS. 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 use-after-free memory vulnerability exists in the ONCRPC XDR (External Data Representation) driver component of Windows Services for NFS. The vulnerability allows remote code execution over the network without requiring authentication or user interaction. An attacker can send specially crafted network packets to trigger the use-after-free condition, leading to arbitrary code execution with the privileges of the NFS service. Microsoft has released security updates to address this issue.

## Affected products

- Microsoft Windows Services for NFS

## Timeline

- 2026-09-08: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78445](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78445)

## Related threats

- [Microsoft Windows Services for NFS ONCRPC XDR Driver out-of-bounds read](https://junglewise.ai/threats/cve-2026-83989-microsoft-windows-services-for-nfs-oncrpc-xdr-driver-out-of)
- [Microsoft Windows Services for NFS heap buffer overflow in ONCRPC XDR Driver](https://junglewise.ai/threats/cve-2026-73024-microsoft-windows-services-for-nfs-heap-buffer-overflow-in-oncrpc)
- [Microsoft Windows Services for NFS ONCRPC XDR Driver information disclosure](https://junglewise.ai/threats/cve-2026-71330-microsoft-windows-services-for-nfs-oncrpc-xdr-driver-information)
- [Microsoft Windows Services for NFS ONCRPC XDR driver use-after-free](https://junglewise.ai/threats/cve-2026-70585-microsoft-windows-services-for-nfs-oncrpc-xdr-driver-use-after)
- [Microsoft Windows Services for NFS ONCRPC XDR Driver use after free](https://junglewise.ai/threats/cve-2026-69595-microsoft-windows-services-for-nfs-oncrpc-xdr-driver-use-after)