CVE-2026-35420: Windows Kernel Elevation of Privilege Vulnerability

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-12 · updated 2026-10-26
Weakness: CWE-122

Description

Heap-based buffer overflow in Windows Kernel allows an authorized attacker to elevate privileges locally.

Affected products

Microsoft Windows Server 2012: r2
Microsoft Windows Server 2016: before 10.0.14393.9140 — fixed in 10.0.14393.9140
Microsoft Windows Server 2019: before 10.0.17763.8755 — fixed in 10.0.17763.8755
Microsoft Windows Server 2022: before 10.0.20348.5074 — fixed in 10.0.20348.5074
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): before 10.0.25398.2330 — fixed in 10.0.25398.2330
Microsoft Windows Server 2025: before 10.0.26100.32772 — fixed in 10.0.26100.32772
Microsoft Windows Server 2012: from 6.2.9200.0 before 6.2.9200.26079 — fixed in 6.2.9200.26079
Microsoft Windows Server 2012 R2: from 6.3.9600.0 before 6.3.9600.23181 — fixed in 6.3.9600.23181
Microsoft Windows Server 2016: from 10.0.14393.0 before 10.0.14393.9140 — fixed in 10.0.14393.9140
Microsoft Windows Server 2019: from 10.0.17763.0 before 10.0.17763.8755 — fixed in 10.0.17763.8755
Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.5139 — fixed in 10.0.20348.5139
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): from 10.0.25398.0 before 10.0.25398.2330 — fixed in 10.0.25398.2330
Microsoft Windows Server 2025: from 10.0.26100.0 before 10.0.26100.32860 — fixed in 10.0.26100.32860

How to fix

Upgrade to a fixed version: Microsoft Windows Server 2016 10.0.14393.9140; Microsoft Windows Server 2019 10.0.17763.8755; Microsoft Windows Server 2022 10.0.20348.5074; Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.2330; Microsoft Windows Server 2025 10.0.26100.32772; Microsoft Windows Server 2012 6.2.9200.26079; Microsoft Windows Server 2012 R2 6.3.9600.23181; Microsoft Windows Server 2016 10.0.14393.9140; Microsoft Windows Server 2019 10.0.17763.8755; Microsoft Windows Server 2022 10.0.20348.5139; Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.2330; Microsoft Windows Server 2025 10.0.26100.32860. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-35420

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