mcp: advertise OAuth via RFC 9728 protected resource metadata#36669
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mcp: advertise OAuth via RFC 9728 protected resource metadata#36669bobbyiliev wants to merge 10 commits into
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May 21, 2026
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I added a test that would be important to fix! host injection
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A payload like attacker.example.net" foo=bar smuggles a " into the header value (accepted, HeaderValue::from_str only blocks CR/LF/control bytes), closing the resource_metadata="..." parameter early. An RFC 7235 parser then reads the URL as https://attacker.example.net.
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A payload like attacker.example.net" foo=bar smuggles a " into the header value (accepted, HeaderValue::from_str only blocks CR/LF/control bytes), closing the resource_metadata="..." parameter early. An RFC 7235 parser then reads the URL as https://attacker.example.net.
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First step toward letting MCP clients that expect the standard OAuth discovery
flow (Claude Desktop Custom Connectors, ChatGPT remote MCP, etc.) connect to
our MCP endpoints. Per the MCP authorization spec,
the resource server MUST implement RFC 9728 Protected Resource Metadata; this
PR adds that piece and the matching 401 challenge.
Fixes https://linear.app/materializeinc/issue/DEX-31/support-oauth-21-authorization-flow-on-the-mcp-endpoints