Is CVE-2026-34351 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-34351 being exploited in the wild.

How severe is CVE-2026-34351?

High severity, with a CVSS score of 7.8, published 12 May 2026.

Which products and versions are affected?

Microsoft Windows All supported versions including Windows 10, 11, and Server.

Is there a fix for CVE-2026-34351?

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-2026-34351 attacked?

It is attacked with local access, in an operating system.

Am I affected by CVE-2026-34351?

Check whether you run Microsoft Windows 11, Microsoft Windows Server or Microsoft Windows 10. 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.

CVE-2026-34351: Microsoft Windows TCP/IP race condition privilege escalation

CVE-2026-34351 · Severity: high · CVSS 7.8 · Published 2026-05-12

A security vulnerability exists in the Windows networking component (TCP/IP) that could allow a user with basic access to a computer to gain full administrative control. By exploiting a timing flaw in how the system handles network data, an attacker can bypass security restrictions to run malicious code with high-level system privileges. This could lead to a complete takeover of the affected machine, allowing the attacker to access sensitive data or disrupt operations.

Technologies: Microsoft Windows 11, Microsoft Windows Server, Microsoft Windows 10. Vendors: Microsoft.

Quick answers

Is CVE-2026-34351 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-34351 being exploited in the wild.
How severe is CVE-2026-34351?: High severity, with a CVSS score of 7.8, published 12 May 2026.
Which products and versions are affected?: Microsoft Windows All supported versions including Windows 10, 11, and Server.
Is there a fix for CVE-2026-34351?: 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-2026-34351 attacked?: It is attacked with local access, in an operating system.
Am I affected by CVE-2026-34351?: Check whether you run Microsoft Windows 11, Microsoft Windows Server or Microsoft Windows 10. 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 race condition vulnerability (CWE-362) exists within the Windows TCP/IP driver due to improper synchronization when accessing shared resources. An attacker with low-privileged local access can exploit this flaw by carefully timing execution threads to manipulate shared memory or state before the system can properly validate or lock it. Successful exploitation allows the attacker to execute arbitrary code in the context of the SYSTEM account, leading to full local privilege escalation (LPE). The vulnerability is reachable locally without user interaction, and Microsoft has released security updates to address the synchronization logic.

Affected products

Microsoft Windows All supported versions including Windows 10, 11, and Server

Timeline

2026-05-12: disclosed: Initial disclosure by Microsoft and NVD
2026-05-12: advisory: Microsoft Security Response Center published the update guide

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-34351

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.