fix(security): enable JWT audience validation and declare MCP resource path#123
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epugh merged 1 commit intoMay 8, 2026
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…e path
Per the MCP Authorization specification, MCP servers MUST validate that
tokens were specifically issued for them — otherwise any valid JWT from
the same IdP for any sibling application is accepted, enabling
token-confusion pivots (CWE-345).
Wires the existing McpServerOAuth2Configurer with:
- resourcePath("/mcp") — declares the canonical resource indicator
surfaced via OAuth 2.0 Protected Resource Metadata (RFC 9728), which
MCP clients use to discover the authorization server.
- validateAudienceClaim(true) — enforces that the JWT "aud" claim
matches that resource indicator (RFC 8707).
Operators must configure their IdP to populate "aud" with the MCP
server's URL. The application-http.properties comment block documents
the required setup for Auth0, Okta, and Keycloak (which does not yet
honor RFC 8707 `resource=` natively and needs an Audience protocol
mapper on a client scope).
Refs:
- MCP Authorization spec, "Token Audience Binding and Validation":
https://modelcontextprotocol.io/specification/2025-06-18/basic/authorization
- RFC 8707 (Resource Indicators):
https://www.rfc-editor.org/rfc/rfc8707.html
- RFC 9728 (Protected Resource Metadata):
https://www.rfc-editor.org/rfc/rfc9728.html
- Keycloak MCP integration docs (Audience mapper workaround):
https://www.keycloak.org/securing-apps/mcp-authz-server
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Signed-off-by: adityamparikh <aditya.m.parikh@gmail.com>
This was referenced May 2, 2026
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Summary
Per the MCP Authorization specification:
Without audience validation, any valid JWT from the same IdP issued for any sibling application is accepted by this server — a classic token-confusion pivot (CWE-345).
This PR wires the existing `McpServerOAuth2Configurer` with:
These options are already provided by the upstream `spring-ai-community/mcp-server-security` library; this PR just turns them on.
Operator impact
When `http.security.enabled=true`, the IdP must populate the JWT `aud` claim with the MCP server's URL. The expanded comment block in `application-http.properties` documents the per-IdP setup:
`http.security.enabled=false` (current default) is unaffected.
Test plan
Note on PR ordering
Touches `HttpSecurityConfiguration.java` and `application-http.properties`, which overlap with PR #121 (CORS allowlist). Whichever lands second will need a small rebase.
🤖 Generated with Claude Code