# CVE-2026-65791: Microsoft Windows iSCSI Target Service heap buffer overflow

Source: https://junglewise.ai/threats/cve-2026-65791-microsoft-windows-iscsi-target-service-heap-buffer-overflow  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-11. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-65791 · Severity: critical · CVSS 9.8 · Published 2026-08-11

Windows iSCSI Target Service is a network storage protocol service used by organizations to enable storage area networking. A heap buffer overflow vulnerability allows an attacker on the network to execute arbitrary code with elevated privileges, potentially compromising entire systems and any data they access.

Technologies: [Microsoft Windows iSCSI Target Service](https://junglewise.ai/threats/technologies/windows-iscsi-target-service). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-65791 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-65791 being exploited in the wild.

**How severe is CVE-2026-65791?** Critical severity, with a CVSS score of 9.8, published 11 August 2026.

**Which products and versions are affected?** Microsoft Windows iSCSI Target Service.

**Is there a fix for CVE-2026-65791?** 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-2026-65791 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-65791?** Check whether you run Microsoft Windows iSCSI Target Service. 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 iSCSI Target Service. The flaw permits an unauthenticated attacker on the network to send crafted iSCSI protocol packets that trigger the buffer overflow, leading to arbitrary code execution. The attack requires network connectivity to the iSCSI service (typically port 3260) but no prior authentication or user interaction. A successful exploit would grant the attacker system-level code execution on the affected host.

## Affected products

- Microsoft Windows iSCSI Target Service

## Timeline

- 2026-08-11: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-65791](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-65791)

## Related threats

- [Windows iSCSI Target Service buffer over-read](https://junglewise.ai/threats/cve-2026-83684-buffer-over-read-in-windows-iscsi-target-service-allows-an)
- [Microsoft Windows iSCSI Target Service uncaught exception denial of service](https://junglewise.ai/threats/cve-2026-69839-microsoft-windows-iscsi-target-service-uncaught-exception-denial)
- [Microsoft Windows iSCSI Target Service null pointer dereference](https://junglewise.ai/threats/cve-2026-65681-microsoft-windows-iscsi-target-service-null-pointer-dereference)
- [Microsoft Windows iSCSI Target Service heap buffer overflow](https://junglewise.ai/threats/cve-2026-65679-microsoft-windows-iscsi-target-service-heap-buffer-overflow)