# CVE-2026-69839: Microsoft Windows iSCSI Target Service uncaught exception denial of service

Source: https://junglewise.ai/threats/cve-2026-69839-microsoft-windows-iscsi-target-service-uncaught-exception-denial  
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-2026-69839 · Severity: medium · CVSS 6.5 · Published 2026-09-08

Windows iSCSI Target Service is a network storage protocol handler used in enterprise environments. An authorized attacker can trigger an uncaught exception in this service, causing it to crash and deny service to legitimate users accessing iSCSI storage resources over the network.

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-2026-69839 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-69839 being exploited in the wild.

**How severe is CVE-2026-69839?** Medium severity, with a CVSS score of 6.5, published 8 September 2026.

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

**Is there a fix for CVE-2026-69839?** 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-2026-69839 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-69839?** 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 an uncaught exception in the Windows iSCSI Target Service that can be triggered by an authenticated attacker over the network. The flaw allows an attacker with valid credentials to send a specially crafted request that causes the service to crash, resulting in denial of service. The attack vector is network-based and requires prior authentication, limiting exposure but still posing operational risk to systems relying on iSCSI storage availability. Microsoft has released security patches to address this issue.

## Affected products

- Microsoft Windows iSCSI Target Service

## Timeline

- 2026-09-08: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69839](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69839)

## 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 heap buffer overflow](https://junglewise.ai/threats/cve-2026-65791-microsoft-windows-iscsi-target-service-heap-buffer-overflow)
- [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)