# CVE-2026-42980: Microsoft Windows NT OS Kernel privilege escalation via integer underflow

Source: https://junglewise.ai/threats/cve-2026-42980-microsoft-windows-nt-os-kernel-privilege-escalation-via-integer  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-09. Updated: 2026-06-09  
License: CC BY 4.0 with a link back

CVE-2026-42980 · Severity: high · CVSS 7.8 · Published 2026-06-09

A security vulnerability has been identified in the core of the Microsoft Windows operating system. This flaw allows a user who already has basic access to a computer to gain full administrative control. Such an exploit could lead to the unauthorized installation of software, data theft, or the complete compromise of the affected system.

Technologies: [Microsoft Windows Nt](https://junglewise.ai/threats/technologies/windows-nt). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-42980 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-42980 being exploited in the wild.

**How severe is CVE-2026-42980?** High severity, with a CVSS score of 7.8, published 9 June 2026.

**Which products and versions are affected?** Microsoft Windows NT OS Kernel.

**Is there a fix for CVE-2026-42980?** 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-2026-42980 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-42980?** Check whether you run Microsoft Windows Nt. 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

An integer underflow (CWE-191) and associated heap-based buffer overflow (CWE-122) exist within the Windows NT OS Kernel. The vulnerability is triggered when the kernel incorrectly handles specific integer calculations, leading to a memory wrap or wraparound condition. An attacker with low-privileged local access can exploit this flaw without any user interaction to execute code in kernel mode. Successful exploitation results in a complete loss of confidentiality, integrity, and availability as the attacker gains SYSTEM-level privileges. Microsoft has released security updates to address this issue.

## Affected products

- Microsoft Windows NT OS Kernel

## Timeline

- 2026-06-09: disclosed
- 2026-06-09: advisory

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42980](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42980)

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