CVE tracker / CVE-2025-55229

CVE-2025-55229

CVE-2025-55229 is the Windows Certificate Spoofing Vulnerability. Microsoft rates it Important, CVSS 5.3. It is not in CISA's Known Exploited Vulnerabilities catalog. Published August 21, 2025.

Risk summary

MediumSpoofing

5.3

CVSS v3 base

0.5%

EPSS: chance of exploitation in 30 days

Medium

Severity

Important

Microsoft's rating

Unlikely

Microsoft: exploitation

In CISA KEV

Microsoft describes it: “Improper verification of cryptographic signature in Windows Certificates allows an unauthorized attacker to perform spoofing over a network.”

How to fix it

Microsoft lists 27 affected products and the update that fixes each:

KB5058379 · fixed build 10.0.19045.5854, 10.0.19044.5854
Windows 10 Version 22H2 for 32-bit Systems, Windows 10 Version 22H2 for ARM64-based Systems, Windows 10 Version 22H2 for x64-based Systems, Windows 10 Version 21H2 for x64-based Systems, Windows 10 Version 21H2 for ARM64-based Systems, and 1 more
KB5058383 · fixed build 10.0.14393.8066
Windows Server 2016 (Server Core installation), Windows Server 2016, Windows 10 Version 1607 for x64-based Systems, Windows 10 Version 1607 for 32-bit Systems
KB5058384 · fixed build 10.0.25398.1611
Windows Server 2022, 23H2 Edition (Server Core installation)
KB5058385 · fixed build 10.0.20348.3692
Windows Server 2022 (Server Core installation), Windows Server 2022
KB5058387 · fixed build 10.0.10240.21014
Windows 10 for x64-based Systems, Windows 10 for 32-bit Systems
KB5058392 · fixed build 10.0.17763.7314
Windows Server 2019 (Server Core installation), Windows Server 2019, Windows 10 Version 1809 for x64-based Systems, Windows 10 Version 1809 for 32-bit Systems
KB5058405 · fixed build 10.0.22631.5335, 10.0.22621.5335
Windows 11 Version 23H2 for x64-based Systems, Windows 11 Version 23H2 for ARM64-based Systems, Windows 11 Version 22H2 for x64-based Systems, Windows 11 Version 22H2 for ARM64-based Systems
KB5058411 · fixed build 10.0.26100.4061
Windows Server 2025, Windows 11 Version 24H2 for x64-based Systems, Windows 11 Version 24H2 for ARM64-based Systems, Windows Server 2025 (Server Core installation)

What Microsoft changed

August 26, 2025: Corrected Download and Article links in the Security Updates table. This is an informational change only.
August 21, 2025: Information published. This CVE was addressed by updates that were released in May 2025, but the CVE was inadvertently omitted from the May 2025 Security Updates. This is an informational change only. Customers who have already installed the May 2025 updates do not need to take any further action.

Details

Weakness: CWE-347: Improper Verification of Cryptographic Signature
Publicly disclosed (Microsoft): No
Exploited (Microsoft): No
Known exploited (CISA KEV): Not listed
Published: August 21, 2025
Last revised: August 26, 2025

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References

Microsoft Security Update Guide NVD CVE record CWE

From Microsoft, CISA, NVD and FIRST data; the Microsoft details were read when this page was opened. Check the references above before you act.