Microsoft Suggests Temporary Registry Hack for Stricken Smart Card Users
When an issue is not an issue, when it's intentional, that's a whole different story. In the case of Microsoft's recent Windows Update in October 2025, smart card authentication was intentionally broken, leaving users with a temporary fix that requires a registry hack.
Last week, Redmond revealed the issue after smart card authentication and other certificate operations started failing following an "improvement" made to Windows in light of CVE-2024-30098. The change required RSA-based smart card certificates to use KSP (Key Storage Provider) instead of CSP (Cryptographic Service Provider), which has caused problems for certificates that rely on CSP.
The issues at hand are quite varied, including an inability to sign documents, smart cards not being recognized as CSP providers in 32-bit applications, and failures in applications that rely on certificate-based authentication. The good news is that a workaround is available until the April 2026 Windows updates, when Microsoft plans to remove it.
The temporary fix requires affected users to set the DisableCapiOverrideForRSA registry key value to 0 on every device. This may seem like an easy solution, but it carries some risk and requires careful consideration. Editing the registry can lead to unexpected behavior, and allowing a user anywhere near the registry is not ideal, especially for administrators.
The issue affects almost every supported version of Windows and Windows Server, as well as some that are no longer supported, such as Windows 10 22H2. For users still on Windows 10, this workaround can be seen as a parting gift from Microsoft, given that the operating system reached its end-of-life on October 14.
There is currently no long-term resolution planned for this issue, as the behavior is by design and up to developers to fix in their authenticating apps. However, the short-term workaround provides some relief until the April 2026 updates, which will remove it from devices.
A Temporary Fix with a Short Lifespan
The temporary registry hack may provide a solution for now, but its lifespan is limited to the April 2026 Windows updates. This means that users and administrators must weigh the benefits of this workaround against the potential risks involved in editing the registry.
A Word of Caution for Administrators
For administrators who will be implementing this fix on devices, it's essential to exercise caution when dealing with the registry. A single misstep can lead to unexpected behavior or even system crashes. It's crucial to carefully review and test the registry hack before applying it to any devices.
A Parting Gift for Windows 10 Users
For users still on Windows 10, this temporary fix may seem like a going-away present from Microsoft. However, it's essential to remember that there is no long-term resolution planned for this issue, and the behavior is by design.