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Allow the end-to-end test's host under DNS rebinding protection - #614
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koic merged 1 commit intoOct 15, 2026
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## Motivation and Context `MCP::Server::OAuth::EndToEndTest` drives the SDK's HTTP client against a Rack stack through WebMock's `to_rack`, which until WebMock 3.32 passed the app no `Host` header. WebMock 3.34.0 fills `HTTP_HOST` in from the request URL, so the transport's DNS rebinding protection, on by default, now refuses `mcp.example.com` with `403 Forbidden: Invalid Host header`, and the test errors with "You are forbidden to make initialize requests" on every CI run since that release. The test now builds the transport with `allowed_hosts: ["mcp.example.com"]`, as a deployment serving that host would, so it passes with either WebMock. The library is unchanged. ## How Has This Been Tested? `test/mcp/server/oauth/end_to_end_test.rb` with WebMock 3.34.0, where it errored before, and with WebMock 3.26.4, where it passed before and still does. ## Breaking Changes None.
koic
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October 15, 2026 08:23
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Motivation and Context
MCP::Server::OAuth::EndToEndTestdrives the SDK's HTTP client against a Rack stack through WebMock'sto_rack, which until WebMock 3.32 passed the app noHostheader. WebMock 3.34.0 fillsHTTP_HOSTin from the request URL, so the transport's DNS rebinding protection, on by default, now refusesmcp.example.comwith403 Forbidden: Invalid Host header, and the test errors with "You are forbidden to make initialize requests" on every CI run since that release.The test now builds the transport with
allowed_hosts: ["mcp.example.com"], as a deployment serving that host would, so it passes with either WebMock. The library is unchanged.How Has This Been Tested?
test/mcp/server/oauth/end_to_end_test.rbwith WebMock 3.34.0, where it errored before, and with WebMock 3.26.4, where it passed before and still does.Breaking Changes
None.
Types of changes
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