fix(mcp): pass SSRF-guarded fetch into OAuth start flow, matching probe/revoke

apps/sim/app/api/mcp/oauth/start/route.test.ts

@@ -17,8 +17,10 @@ import {
 import { NextRequest } from 'next/server'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
-const { mockMcpAuth } = vi.hoisted(() => ({
+const { mockMcpAuth, mockCreateSsrfGuardedMcpFetch, mockGuardedFetch } = vi.hoisted(() => ({
  mockMcpAuth: vi.fn(),
+ mockCreateSsrfGuardedMcpFetch: vi.fn(),
+ mockGuardedFetch: vi.fn(),
 }))
 
 vi.mock('@sim/db', () => dbChainMock)
@@ -31,6 +33,9 @@ vi.mock('drizzle-orm', () => ({
 vi.mock('@modelcontextprotocol/sdk/client/auth.js', () => ({
  auth: mockMcpAuth,
 }))
+vi.mock('@/lib/mcp/pinned-fetch', () => ({
+ createSsrfGuardedMcpFetch: mockCreateSsrfGuardedMcpFetch,
+}))
 vi.mock('@/lib/auth/hybrid', () => hybridAuthMock)
 vi.mock('@/lib/workspaces/permissions/utils', () => permissionsMock)
 vi.mock('@/lib/mcp/oauth', () => mcpOauthMock)
@@ -73,6 +78,21 @@ describe('MCP OAuth start route', () => {
  })
  mcpOauthMockFns.mockLoadPreregisteredClient.mockResolvedValue(undefined)
  mockMcpAuth.mockRejectedValue(new McpOauthRedirectRequiredMock('https://mcp.exa.ai/authorize'))
+ mockCreateSsrfGuardedMcpFetch.mockReturnValue(mockGuardedFetch)
+ })
+
+ it('routes OAuth discovery through the SSRF-guarded fetch', async () => {
+ const request = new NextRequest(
+ 'http://localhost:3000/api/mcp/oauth/start?workspaceId=workspace-1&serverId=server-1'
+ )
+
+ await GET(request)
+
+ expect(mockCreateSsrfGuardedMcpFetch).toHaveBeenCalledTimes(1)
+ expect(mockMcpAuth).toHaveBeenCalledWith(
+ expect.anything(),
+ expect.objectContaining({ serverUrl: 'https://mcp.exa.ai/mcp', fetchFn: mockGuardedFetch })
+ )
  })
 
  it('requires workspace write permission via MCP auth middleware', async () => {

apps/sim/app/api/mcp/oauth/start/route.ts

@@ -20,6 +20,7 @@ import {
  SimMcpOauthProvider,
  setOauthRowUser,
 } from '@/lib/mcp/oauth'
+import { createSsrfGuardedMcpFetch } from '@/lib/mcp/pinned-fetch'
 import { createMcpErrorResponse } from '@/lib/mcp/utils'
 
 const logger = createLogger('McpOauthStartAPI')
@@ -129,7 +130,10 @@ export const GET = withRouteHandler(
  const provider = new SimMcpOauthProvider({ row, preregistered })
 
  try {
- const result = await mcpAuth(provider, { serverUrl: server.url })
+ const result = await mcpAuth(provider, {
+ serverUrl: server.url,
+ fetchFn: createSsrfGuardedMcpFetch(),
+ })
  if (result === 'AUTHORIZED') {
  return NextResponse.json({ status: 'already_authorized' })
  }