Quick answers
- Is CVE-2026-40413 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-40413 being exploited in the wild.
- How severe is CVE-2026-40413?
- High severity, with a CVSS score of 7.4, published 12 May 2026.
- Which products and versions are affected?
- Microsoft Windows 10 1607, 1809, 21H2, 22H2; Microsoft Windows 11 23H2, 24H2, 25H2, 26H1; Microsoft Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025, 23H2.
- Is there a fix for CVE-2026-40413?
- 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-2026-40413 attacked?
- It is attacked from the adjacent network, in an operating system.
- Am I affected by CVE-2026-40413?
- Check whether you run Microsoft Windows. 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 vulnerability (CWE-476) exists within the Windows TCP/IP protocol driver. An unauthenticated attacker can exploit this flaw by sending specially crafted network packets over an adjacent network (Layer 2 proximity). Successful exploitation results in a kernel-mode crash (Bug Check), leading to a complete denial of service for the target system. The vulnerability affects a wide range of Windows client and server versions, and Microsoft has released security updates to address the issue.
Affected products
- Microsoft Windows 10 1607, 1809, 21H2, 22H2
- Microsoft Windows 11 23H2, 24H2, 25H2, 26H1
- Microsoft Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025, 23H2
Timeline
- 2026-05-12: disclosed
- 2026-05-12: advisory: Microsoft released the security update guide for this vulnerability.