Microsoft Windows October 2025 security update smart card and certificate disruption
Service Disruption
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Microsoft's October 2025 Windows security updates are causing smart card authentication and certificate-based authentication failures across Windows 10, Windows 11, and Windows Server, disrupting document signing and access on affected systems. The issue comes from a hardening change in Windows Cryptographic Services that shifts RSA smart card certificates from CSP to KSP. Microsoft says affected users can temporarily work around the problem by setting DisableCapiOverrideForRSA to `0`, with the registry key slated for removal in April 2026.
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Timeline
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20.10.2025 17:21 2 articles · 7mo ago
Microsoft Windows October 2025 security update smart card and certificate disruption
Initial DisclosureAfter installation of the **October 2025 Windows security update**, some systems began failing **smart card** and **certificate-based** operations. Microsoft linked the breakage to a security hardening change in **Windows Cryptographic Services**.
Show sources
- Microsoft warns of Windows smart card auth issues after October updates — www.bleepingcomputer.com — 20.10.2025 17:21
- Microsoft warns of Windows smart card auth issues after October updates — www.bleepingcomputer.com — 20.10.2025 17:21