The CSRF middleware read the request body via request.form() to extract
the csrf_token form field, then handed the already-consumed ASGI receive
to the downstream app. The endpoint's own request.form()/body() then
blocked indefinitely waiting for body bytes that would never arrive,
hanging the request until the client disconnected (ClientDisconnect).
Only native form POSTs hit this path: htmx requests carry the token in
the X-CSRF-Token header and skip the body read. The OIDC consent form is
a plain form with the token in the body, so authorization consent hung.
Buffer the body when falling back to the form token and replay it to the
downstream app via a wrapped receive. Header-token requests are
unchanged. Adds a regression test where the endpoint reads the body after
body-token CSRF validation.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
