CVE-2026-42904 | Windows TCP/IP Elevation of Privilege Vulnerability

Heap-based buffer overflow in Windows TCP/IP allows an unauthorized attacker to elevate privileges over an adjacent network.

Published: 2026-06-09 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-42904 is rated Moderate Risk (50.7/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.44%). Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-42904

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-23 0.33% 0.44% +0.11%
2 2026-06-15 0.11% 0.33% +0.22%
3 2026-06-10 0.11%

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-42904

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.6 3.1 CRITICAL
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:A)
Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
2.8 6.0 [email protected]

Weakness enumeration for CVE-2026-42904

GitHub Security Advisory for CVE-2026-42904

GHSA-3f78-xrf3-9xc8 · Severity: critical — Heap-based buffer overflow in Windows TCP/IP allows an unauthorized attacker to elevate...

Affected software / configurations for CVE-2026-42904

Vendor Product Version Raw CPE
microsoft windows_10_21h2 < 10.0.19044.7417 cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:arm64:*
microsoft windows_10_21h2 < 10.0.19044.7417 cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:*
microsoft windows_10_21h2 < 10.0.19044.7417 cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x86:*
microsoft windows_10_22h2 < 10.0.19045.7417 cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:arm64:*
microsoft windows_10_22h2 < 10.0.19045.7417 cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:*
microsoft windows_10_22h2 < 10.0.19045.7417 cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x86:*
microsoft windows_11_23h2 < 10.0.22631.7219 cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:*
microsoft windows_11_23h2 < 10.0.22631.7219 cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:*
microsoft windows_11_24h2 < 10.0.26100.8655 cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:*
microsoft windows_11_24h2 < 10.0.26100.8655 cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:*
microsoft windows_11_25h2 < 10.0.26200.8655 cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:*
microsoft windows_11_25h2 < 10.0.26200.8655 cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:*
microsoft windows_11_26h1 < 10.0.28000.2269 cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:arm64:*
microsoft windows_11_26h1 < 10.0.28000.2269 cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:x64:*
microsoft windows_server_2022 < 10.0.20348.5256 cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
microsoft windows_server_2025 < 10.0.26100.32995 cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:*

References for CVE-2026-42904

cvelogic Threat Intelligence