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Critical severity · published Jun 9, 2026
CVE-2026-42904
Windows TCP/IP Elevation of Privilege Vulnerability
9.6
CVSS
0.4%
EPSS
No
On KEV
Description
Heap-based buffer overflow in Windows TCP/IP allows an unauthorized attacker to elevate privileges over an adjacent network.
CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
W1
Windows 10 Version 21H2 · Microsoft
10.0.19044.0 before 10.0.19044.7417 · source: vendor
W1
Windows 10 Version 22H2 · Microsoft
10.0.19045.0 before 10.0.19045.7417 · source: vendor
W1
Windows 11 Version 24H2 · Microsoft
10.0.26100.0 before 10.0.26100.8655 · source: vendor
W1
Windows 11 Version 25H2 · Microsoft
10.0.26200.0 before 10.0.26200.8655 · source: vendor
W1
Windows 11 version 23H2 · Microsoft
10.0.22631.0 before 10.0.22631.7219; 10.0.22631.0 before 10.0.22631.7219 · source: vendor
W1
Windows 11 version 26H1 · Microsoft
10.0.28000.0 before 10.0.28000.2269 · source: vendor
WS
Windows Server 2022 · Microsoft
10.0.20348.0 before 10.0.20348.5256 · source: vendor, NVD
WS
Windows Server 2025 · Microsoft
10.0.26100.0 before 10.0.26100.32995 · source: vendor, NVD
WS
Windows Server 2025 (Server Core installation) · Microsoft
10.0.26100.0 before 10.0.26100.32995 · source: vendor
W1
Windows 10 21h2 · Microsoft
before 10.0.19044.7417; before 10.0.19044.7417; before 10.0.19044.7417 · source: NVD
W1
Windows 10 22h2 · Microsoft
before 10.0.19045.7417; before 10.0.19045.7417; before 10.0.19045.7417 · source: NVD
W1
Windows 11 23h2 · Microsoft
before 10.0.22631.7219; before 10.0.22631.7219 · source: NVD
Affected product
W1
Windows 10 Version 21H2
Microsoft
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42904
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-42904
Vendor Advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42904
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