# CVE-2026-72936: Microsoft Windows SMB Client use-after-free remote code execution

Source: https://junglewise.ai/threats/cve-2026-72936-microsoft-windows-smb-client-use-after-free-remote-code-execution  
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-2026-72936 · Severity: high · CVSS 8.1 · Published 2026-09-08

A use-after-free vulnerability in Windows SMB Client allows an attacker to execute arbitrary code on a Windows system over the network without authentication. SMB Client is a core component used for file sharing and network access across Windows systems. Exploitation could lead to complete system compromise and lateral movement within an organization.

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-2026-72936 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-72936 being exploited in the wild.

**How severe is CVE-2026-72936?** High severity, with a CVSS score of 8.1, published 8 September 2026.

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

**Is there a fix for CVE-2026-72936?** 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-2026-72936 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-72936?** 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

A use-after-free vulnerability exists in the Windows SMB Client due to improper memory management when handling SMB protocol messages. The vulnerability is triggered over the network (SMB protocol, port 445) and requires no user interaction or prior authentication. An attacker can craft a malicious SMB message to trigger the use-after-free condition, leading to arbitrary code execution with the privileges of the SMB Client service. The vulnerability has a CVSS v3.1 score of 8.1 and is not currently known to be exploited in the wild.

## Affected products

- Microsoft Windows SMB Client

## Timeline

- 2026-09-08: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-72936](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-72936)

## 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)
- [Windows SMB Client heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-112971-heap-based-buffer-overflow-in-windows-smb-client-allows-an)
- [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)