CVE-2025-47981: SPNEGO Extended Negotiation (NEGOEX) Security Mechanism Remote Code Execution Vulnerability

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 41.1% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2025-07-08 · updated 2026-06-17
Weakness: CWE-122

Description

Heap-based buffer overflow in Windows SPNEGO Extended Negotiation allows an unauthorized attacker to execute code over a network.

Affected products

Microsoft Windows 10 Version 1507: before 10.0.10240.21073 — fixed in 10.0.10240.21073
Microsoft Windows 10 1607: before 10.0.14393.8246 — fixed in 10.0.14393.8246
Microsoft Windows 10: before 10.0.17763.7558 — fixed in 10.0.17763.7558
Microsoft Windows 10: before 10.0.19044.6093 — fixed in 10.0.19044.6093
Microsoft Windows 10: before 10.0.19045.6093 — fixed in 10.0.19045.6093
Microsoft Windows 11: before 10.0.22621.5624 — fixed in 10.0.22621.5624
Microsoft Windows 11: before 10.0.22631.5624 — fixed in 10.0.22631.5624
Microsoft Windows 11: before 10.0.26100.4652 — fixed in 10.0.26100.4652
Microsoft Windows Server 2008: r2-sp1
Microsoft Windows Server 2012: r2
Microsoft Windows Server 2016: before 10.0.14393.8246 — fixed in 10.0.14393.8246
Microsoft Windows Server 2019: before 10.0.17763.7558 — fixed in 10.0.17763.7558
Microsoft Windows Server 2022: before 10.0.20348.3932 — fixed in 10.0.20348.3932
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): before 10.0.25398.1732 — fixed in 10.0.25398.1732
Microsoft Windows Server 2025: before 10.0.26100.4652 — fixed in 10.0.26100.4652
Microsoft Windows 10 Version 1507: from 10.0.10240.0 before 10.0.10240.21073 — fixed in 10.0.10240.21073
Microsoft Windows 10 1607: from 10.0.14393.0 before 10.0.14393.8246 — fixed in 10.0.14393.8246
Microsoft Windows 10: from 10.0.17763.0 before 10.0.17763.7558 — fixed in 10.0.17763.7558
Microsoft Windows 10: from 10.0.19044.0 before 10.0.19044.6093 — fixed in 10.0.19044.6093
Microsoft Windows 10: from 10.0.19045.0 before 10.0.19045.6093 — fixed in 10.0.19045.6093
Microsoft Windows 11: from 10.0.22621.0 before 10.0.22621.5624 — fixed in 10.0.22621.5624
Microsoft Windows 11 version 22H3: from 10.0.22631.0 before 10.0.22631.5624 — fixed in 10.0.22631.5624
Microsoft Windows 11: from 10.0.22631.0 before 10.0.22631.5624 — fixed in 10.0.22631.5624
Microsoft Windows 11: from 10.0.26100.0 before 10.0.26100.4652 — fixed in 10.0.26100.4652
Microsoft Windows Server 2008 R2 Service Pack 1: from 6.1.7601.0 before 6.1.7601.27820 — fixed in 6.1.7601.27820
Microsoft Windows Server 2012: from 6.2.9200.0 before 6.2.9200.25573 — fixed in 6.2.9200.25573
Microsoft Windows Server 2012 R2: from 6.3.9600.0 before 6.3.9600.22676 — fixed in 6.3.9600.22676
Microsoft Windows Server 2016: from 10.0.14393.0 before 10.0.14393.8246 — fixed in 10.0.14393.8246
Microsoft Windows Server 2019: from 10.0.17763.0 before 10.0.17763.7558 — fixed in 10.0.17763.7558
Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.3932 — fixed in 10.0.20348.3932

How to fix

Upgrade to a fixed version: Microsoft Windows 10 Version 1507 10.0.10240.21073; Microsoft Windows 10 1607 10.0.14393.8246; Microsoft Windows 10 10.0.17763.7558; Microsoft Windows 10 10.0.19044.6093; Microsoft Windows 10 10.0.19045.6093; Microsoft Windows 11 10.0.22621.5624; Microsoft Windows 11 10.0.22631.5624; Microsoft Windows 11 10.0.26100.4652; Microsoft Windows Server 2016 10.0.14393.8246; Microsoft Windows Server 2019 10.0.17763.7558; Microsoft Windows Server 2022 10.0.20348.3932; Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.1732. Check the vendor advisory for mitigations.

References

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