# CVE-2026-85859: Windows Message Queuing null pointer dereference denial of service

Source: https://junglewise.ai/threats/cve-2026-85859-null-pointer-dereference-in-windows-message-queuing-queue-manager  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-85859 · Severity: medium · CVSS 6.5 · Published 2026-10-13

Windows Message Queuing is a service that allows applications to communicate across networks. A null pointer vulnerability in the Queue Manager allows an authorized attacker to crash the service and disrupt message delivery, causing denial of service.

Technologies: [Microsoft Windows Message Queuing](https://junglewise.ai/threats/technologies/windows-message-queuing). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-85859 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-85859 being exploited in the wild.

**How severe is CVE-2026-85859?** Medium severity, with a CVSS score of 6.5, published 13 October 2026.

**Which products and versions are affected?** Microsoft Windows Message Queuing <UNKNOWN>.

**Is there a fix for CVE-2026-85859?** 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-2026-85859 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2026-85859?** Check whether you run Microsoft Windows Message Queuing at an affected version. 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 null pointer dereference in the Windows Message Queuing Queue Manager can be triggered by an authorized attacker over the network. The vulnerability allows an attacker with valid credentials to send a specially crafted message that causes the service to crash, resulting in denial of service. This requires authentication and network access to trigger.

## Affected products

- Microsoft Windows Message Queuing <UNKNOWN>

## Timeline

- 2026-10-13: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85859](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85859)

## Related threats

- [Windows Message Queuing use after free in Queue Manager](https://junglewise.ai/threats/cve-2026-119967-use-after-free-in-windows-message-queuing-queue-manager-allows)
- [Windows Message Queuing double free](https://junglewise.ai/threats/cve-2026-119964-double-free-in-windows-message-queuing-allows-an-unauthorized)
- [Windows Message Queuing double free remote code execution](https://junglewise.ai/threats/cve-2026-119963-double-free-in-windows-message-queuing-allows-an-unauthorized)
- [Windows Message Queuing improper input validation DoS](https://junglewise.ai/threats/cve-2026-119848-improper-input-validation-in-windows-message-queuing-allows-an)
- [Windows Message Queuing privilege escalation via untrusted pointer dereference](https://junglewise.ai/threats/cve-2026-119833-untrusted-pointer-dereference-in-windows-message-queuing-allows)