CVE-2025-54895: SPNEGO Extended Negotiation (NEGOEX) Security Mechanism 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: 2025-09-09 · updated 2026-06-17
Weakness: CWE-190

Description

Integer overflow or wraparound in Windows SPNEGO Extended Negotiation allows an authorized attacker to elevate privileges locally.

Affected products

Microsoft Windows 10 Version 1507: before 10.0.10240.21128 — fixed in 10.0.10240.21128
Microsoft Windows 10 1607: before 10.0.14393.8422 — fixed in 10.0.14393.8422
Microsoft Windows 10: before 10.0.17763.7792 — fixed in 10.0.17763.7792
Microsoft Windows 10: before 10.0.19044.6332 — fixed in 10.0.19044.6332
Microsoft Windows 10: before 10.0.19045.6332 — fixed in 10.0.19045.6332
Microsoft Windows 11: before 10.0.22621.5909 — fixed in 10.0.22621.5909
Microsoft Windows 11: before 10.0.22631.5909 — fixed in 10.0.22631.5909
Microsoft Windows 11: before 10.0.26100.6508 — fixed in 10.0.26100.6508
Microsoft Windows Server 2008: r2-sp1
Microsoft Windows Server 2012: r2
Microsoft Windows Server 2016: before 10.0.14393.8422 — fixed in 10.0.14393.8422
Microsoft Windows Server 2019: before 10.0.17763.7792 — fixed in 10.0.17763.7792
Microsoft Windows Server 2022: before 10.0.20348.4106 — fixed in 10.0.20348.4106
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): before 10.0.25398.1849 — fixed in 10.0.25398.1849
Microsoft Windows Server 2025: before 10.0.26100.6508 — fixed in 10.0.26100.6508
Microsoft Windows 10 Version 1507: from 10.0.10240.0 before 10.0.10240.21128 — fixed in 10.0.10240.21128
Microsoft Windows 10 1607: from 10.0.14393.0 before 10.0.14393.8422 — fixed in 10.0.14393.8422
Microsoft Windows 10: from 10.0.17763.0 before 10.0.17763.7792 — fixed in 10.0.17763.7792
Microsoft Windows 10: from 10.0.19044.0 before 10.0.19044.6332 — fixed in 10.0.19044.6332
Microsoft Windows 10: from 10.0.19045.0 before 10.0.19045.6332 — fixed in 10.0.19045.6332
Microsoft Windows 11: from 10.0.22621.0 before 10.0.22621.5909 — fixed in 10.0.22621.5909
Microsoft Windows 11 version 22H3: from 10.0.22631.0 before 10.0.22631.5909 — fixed in 10.0.22631.5909
Microsoft Windows 11: from 10.0.22631.0 before 10.0.22631.5909 — fixed in 10.0.22631.5909
Microsoft Windows 11: from 10.0.26100.0 before 10.0.26100.6584 — fixed in 10.0.26100.6584
Microsoft Windows Server 2008 R2 Service Pack 1: from 6.1.7601.0 before 6.1.7601.27929 — fixed in 6.1.7601.27929
Microsoft Windows Server 2012: from 6.2.9200.0 before 6.2.9200.25675 — fixed in 6.2.9200.25675
Microsoft Windows Server 2012 R2: from 6.3.9600.0 before 6.3.9600.22774 — fixed in 6.3.9600.22774
Microsoft Windows Server 2016: from 10.0.14393.0 before 10.0.14393.8422 — fixed in 10.0.14393.8422
Microsoft Windows Server 2019: from 10.0.17763.0 before 10.0.17763.7792 — fixed in 10.0.17763.7792
Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.4171 — fixed in 10.0.20348.4171

How to fix

Upgrade to a fixed version: Microsoft Windows 10 Version 1507 10.0.10240.21128; Microsoft Windows 10 1607 10.0.14393.8422; Microsoft Windows 10 10.0.17763.7792; Microsoft Windows 10 10.0.19044.6332; Microsoft Windows 10 10.0.19045.6332; Microsoft Windows 11 10.0.22621.5909; Microsoft Windows 11 10.0.22631.5909; Microsoft Windows 11 10.0.26100.6508; Microsoft Windows Server 2016 10.0.14393.8422; Microsoft Windows Server 2019 10.0.17763.7792; Microsoft Windows Server 2022 10.0.20348.4106; Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.1849. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-54895

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