CVE-2025-55229: Windows Certificate Spoofing Vulnerability

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-08-21 · updated 2026-06-17
Weakness: CWE-347

Description

Improper verification of cryptographic signature in Windows Certificates allows an unauthorized attacker to perform spoofing over a network.

Affected products

Microsoft Windows 10 Version 1507: before 10.0.10240.21014 — fixed in 10.0.10240.21014
Microsoft Windows 10 1607: before 10.0.14393.8066 — fixed in 10.0.14393.8066
Microsoft Windows 10: before 10.0.17763.7314 — fixed in 10.0.17763.7314
Microsoft Windows 10: before 10.0.19044.5854 — fixed in 10.0.19044.5854
Microsoft Windows 10: before 10.0.19045.5854 — fixed in 10.0.19045.5854
Microsoft Windows 11: before 10.0.22621.5335 — fixed in 10.0.22621.5335
Microsoft Windows 11: before 10.0.22631.5335 — fixed in 10.0.22631.5335
Microsoft Windows 11: before 10.0.26100.4061 — fixed in 10.0.26100.4061
Microsoft Windows Server 2016: before 10.0.14393.8066 — fixed in 10.0.14393.8066
Microsoft Windows Server 2019: before 10.0.17763.7314 — fixed in 10.0.17763.7314
Microsoft Windows Server 2022: before 10.0.20348.3630 — fixed in 10.0.20348.3630
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): before 10.0.25398.1611 — fixed in 10.0.25398.1611
Microsoft Windows Server 2025: before 10.0.26100.4061 — fixed in 10.0.26100.4061
Microsoft Windows 10 Version 1507: from 10.0.10240.0 before 10.0.10240.21014 — fixed in 10.0.10240.21014
Microsoft Windows 10 1607: from 10.0.14393.0 before 10.0.14393.8066 — fixed in 10.0.14393.8066
Microsoft Windows 10: from 10.0.17763.0 before 10.0.17763.7314 — fixed in 10.0.17763.7314
Microsoft Windows 10: from 10.0.19044.0 before 10.0.19044.5854 — fixed in 10.0.19044.5854
Microsoft Windows 10: from 10.0.19045.0 before 10.0.19045.5854 — fixed in 10.0.19045.5854
Microsoft Windows 11: from 10.0.22621.0 before 10.0.22621.5335 — fixed in 10.0.22621.5335
Microsoft Windows 11 version 22H3: from 10.0.22631.0 before 10.0.22631.5335 — fixed in 10.0.22631.5335
Microsoft Windows 11: from 10.0.22631.0 before 10.0.22631.5335 — fixed in 10.0.22631.5335
Microsoft Windows 11: from 10.0.26100.0 before 10.0.26100.4061 — fixed in 10.0.26100.4061
Microsoft Windows Server 2016: from 10.0.14393.0 before 10.0.14393.8066 — fixed in 10.0.14393.8066
Microsoft Windows Server 2019: from 10.0.17763.0 before 10.0.17763.7314 — fixed in 10.0.17763.7314
Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.3692 — fixed in 10.0.20348.3692
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): from 10.0.25398.0 before 10.0.25398.1611 — fixed in 10.0.25398.1611
Microsoft Windows Server 2025: from 10.0.26100.0 before 10.0.26100.4061 — fixed in 10.0.26100.4061

How to fix

Upgrade to a fixed version: Microsoft Windows 10 Version 1507 10.0.10240.21014; Microsoft Windows 10 1607 10.0.14393.8066; Microsoft Windows 10 10.0.17763.7314; Microsoft Windows 10 10.0.19044.5854; Microsoft Windows 10 10.0.19045.5854; Microsoft Windows 11 10.0.22621.5335; Microsoft Windows 11 10.0.22631.5335; Microsoft Windows 11 10.0.26100.4061; Microsoft Windows Server 2016 10.0.14393.8066; Microsoft Windows Server 2019 10.0.17763.7314; Microsoft Windows Server 2022 10.0.20348.3630; Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.1611. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-55229

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