# CVE-2026-112971: Windows SMB Client heap-based buffer overflow

Source: https://junglewise.ai/threats/cve-2026-112971-heap-based-buffer-overflow-in-windows-smb-client-allows-an  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-10. Updated: 2026-11-10  
License: CC BY 4.0 with a link back

CVE-2026-112971 · Severity: high · CVSS 7 · Published 2026-11-10

A heap-based buffer overflow exists in Windows SMB Client, the component that enables communication with network file shares and printers. An authenticated local attacker can exploit this vulnerability to gain elevated system privileges, potentially allowing them to take complete control of the affected computer.

Technologies: [Microsoft Windows SMB Client](https://junglewise.ai/threats/technologies/windows-smb-client). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-112971 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-112971 being exploited in the wild.

**How severe is CVE-2026-112971?** High severity, with a CVSS score of 7, published 10 November 2026.

**Which products and versions are affected?** Microsoft Windows SMB Client.

**Is there a fix for CVE-2026-112971?** 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-2026-112971 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-112971?** Check whether you run Microsoft Windows SMB Client. 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

The vulnerability is a heap-based buffer overflow in the Windows SMB Client that can be triggered by an authenticated local attacker. Exploitation requires local access and existing authentication credentials on the system. A successful exploit results in privilege escalation to SYSTEM level.

## Affected products

- Microsoft Windows SMB Client

## Timeline

- 2026-11-10: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-112971](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-112971)

## Related threats

- [Windows SMB Client privilege escalation via untrusted pointer dereference](https://junglewise.ai/threats/cve-2026-119870-untrusted-pointer-dereference-in-windows-smb-client-allows-an)
- [Microsoft Windows SMB Client use-after-free remote code execution](https://junglewise.ai/threats/cve-2026-72936-microsoft-windows-smb-client-use-after-free-remote-code-execution)
- [Microsoft Windows SMB Client out-of-bounds read](https://junglewise.ai/threats/cve-2026-69618-microsoft-windows-smb-client-out-of-bounds-read)
- [Microsoft Windows SMB Client buffer over-read](https://junglewise.ai/threats/cve-2026-65794-microsoft-windows-smb-client-buffer-over-read)
- [Microsoft Windows SMB Client use after free privilege escalation](https://junglewise.ai/threats/cve-2026-40410-microsoft-windows-smb-client-use-after-free-privilege-escalation)