Self-hosted WCF http stopped working after October 2025 update — any code-level workaround? [closed]

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I created a new topic because all the previous ones about this issue were already closed, but mine got closed as well.

After installing the October 2025 cumulative update our WCF service hosted with ServiceHost stopped working.

There is an exception at service starting:

System.ServiceModel.CommunicationException: An error occurred while receiving the HTTP response to http(s)://<host>:<port>/ServicePath This could be due to the service endpoint binding not using the HTTP protocol. This could also be due to an HTTP request context being aborted by the server (possibly due to the service shutting down). See server logs for more details.

The service uses BasicHttpBinding but changing to BasicHttpsBinding also results the same error. After whole day of trying I've found workaround - changing binding to NetTcpBinding resolves the problem without uninstalling the update.

I’ve seen similar reports on Microsoft Learn:

KB5066835 update causing IIS Service to not work

Localhost not working anymore after 2025-10 cumulative update Windows 11

Many users there are reporting the same behavior — not only with WCF but also with IIS and other .NET HTTP-based services. There are also multiple related discussions here describing similar symptoms, so this definitely seems to be a broader issue introduced by the October 2025 update.

However, suggested workaround so far is to uninstall the update, which isn’t an option for us. That’s why I’m posting here — to ask if there’s any code-level or installer-level workaround that can be applied directly in the application or through our WiX installer.

We can’t modify client systems or require manual configuration, so the fix must come from within the app itself. Would migrating this service to CoreWCF (running on .NET 6/8 with Kestrel) fully resolve the issue, or is there another code-level workaround to make HTTP/HTTPS self-hosted .NET services work again?

• user4157124: This question is similar to: Localhost applications failing after installing "2025-10 Cumulative Update for Windows 11 Version 24H2 for x64-based Systems (KB5066835) (26100.6899)". If you believe it’s different, please edit the question, make it clear how it’s different and/or how the answers on that question are not helpful for your problem.
• Lex Li: If you want Microsoft to confirm something, your first act is to contact them, not here. Use support.microsoft.com to get started please. There are enough issues with patches in the past few months, so make sure you put enough pressure if you are a big customer.
• user4157124: @martindsa Do not include solution to question please.
• user4157124: @martindsa "... is there another code-level workaround to make HTTP/HTTPS self-hosted .NET services work again?" Rhetorical question of course. "We can’t modify client systems or require manual configuration ..." Nor should you. The question after its edit became an XY problem. It's an issue between your clients and Microsoft.