Vulnerability · Published Jun 9, 2026 · Assigned by microsoft
CVE-2026-42904Windows TCP/IP Elevation of Privilege Vulnerability
Critical 9.6
In plain English
A critical-severity heap buffer overflow in Windows 10 Version 21H2 from Microsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 38% of all known vulnerabilities).
Severity (CVSS 3.1)9.6Critical
Exploit odds (30 days)0.4%top 61.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Heap-based buffer overflow in Windows TCP/IP allows an unauthorized attacker to elevate privileges over an adjacent network.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Windows 10 Version 21H2 | 10.0.19044.0 – before 10.0.19044.7417 |
| Microsoft | Windows 10 Version 22H2 | 10.0.19045.0 – before 10.0.19045.7417 |
| Microsoft | Windows 11 version 23H2 | 10.0.22631.0 – before 10.0.22631.7219 |
| Microsoft | Windows 11 Version 23H2 | 10.0.22631.0 – before 10.0.22631.7219 |
| Microsoft | Windows 11 Version 24H2 | 10.0.26100.0 – before 10.0.26100.8655 |
| Microsoft | Windows 11 Version 25H2 | 10.0.26200.0 – before 10.0.26200.8655 |
| Microsoft | Windows 11 version 26H1 | 10.0.28000.0 – before 10.0.28000.2269 |
| Microsoft | Windows Server 2022 | 10.0.20348.0 – before 10.0.20348.5256 |
| Microsoft | Windows Server 2025 | 10.0.26100.0 – before 10.0.26100.32995 |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 – before 10.0.26100.32995 |
Weakness: CWE-122 · Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C
References
- Windows TCP/IP Elevation of Privilege Vulnerability vendor-advisory, patch