Vulnerability · Published May 12, 2026 · Assigned by microsoft
CVE-2026-40405Windows TCP/IP Denial of Service Vulnerability
High 7.5
In plain English
A high-severity null pointer dereference in Windows 11 Version 24H2 from Microsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 65% of all known vulnerabilities).
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)1.1%top 34.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Null pointer dereference in Windows TCP/IP allows an unauthorized attacker to deny service over a network.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Windows 11 Version 24H2 | 10.0.26100.0 – before 10.0.26100.8457 |
| Microsoft | Windows 11 Version 25H2 | 10.0.26200.0 – before 10.0.26200.8457 |
| Microsoft | Windows 11 version 26H1 | 10.0.28000.0 – before 10.0.28000.2113 |
| Microsoft | Windows Server 2025 | 10.0.26100.0 – before 10.0.26100.32860 |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 – before 10.0.26100.32860 |
Weakness: CWE-476 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C
References
- Windows TCP/IP Denial of Service Vulnerability vendor-advisory, patch