Microsoft has identified that the October 2025 Windows security updates cause smart card authentication and certificate issues across all Windows 10, Windows 11, and Windows Server versions. Users experiencing these problems can manually resolve them by modifying the registry, though the fix will be removed in April 2026. #WindowsSecurity #SmartCardIssues
Keypoints
- The October 2025 Windows updates introduce issues with smart card authentication due to a security feature change.
- Problems include failed document signing, application errors, and unrecognized CSP providers in apps.
- The issue is linked to a security improvement that switches from CSP to KSP for RSA smart card certificates.
- Users can temporarily fix the problem by editing the registry to disable the CapiOverrideForRSA setting.
- Microsoft plans to remove the registry fix in April 2026 and recommends working with application vendors for a long-term solution.