CVE-2026-54547

X-Pipeboard-Token Header Auth Bypass Reuses Operator Meta Token Summary AuthInjectionMiddleware in meta-ads-mcp rejects HTTP MCP requests only when both auth_token and pipeboard_token are absent. Because extract_token_from_headers() does not recognise the X-Pipeboard-Token header, an attacker who sends that header with any arbitrary value produces auth_token = None and pipeboard_token = <attacker value>, making the guard condition evaluate to False and passing the request through. No authentication context is set; the token getter falls back to the server operator's META_ACCESS_TOKEN environment variable. Every subsequent MCP tool call executes with the operator's Meta credentials, allowing an unauthenticated network caller to read and write the operator's Meta Ads data. Details The vulnerable condition is at meta_ads_mcp/core/http_auth_integration.py:259: http_auth_integration.py:255-260 auth_token = FastMCPAuthIntegration.extract_token_from_headers(dict(request.headers)) pipeboard_token = FastMCPAuthIntegration.extract_pipeboard_token_from_headers(dict(request.headers)) if not auth_token and not pipeboard_token: # ← bypass condition return Response(..., status_code=401) extract_token_from_headers() (lines 77–95) recognises only Authorization: Bearer, X-META-ACCESS-TOKEN, and X-PIPEBOARD-API-TOKEN. It does not recognise X-Pipeboard-Token, so that header never populates auth_token. extract_pipeboard_token_from_headers() (line 108) does recognise X-Pipeboard-Token, so sending that header alone produces: auth_token = None # not set → guard reads False for left operand pipeboard_token = "<anything>" # truthy → guard reads False for right operand → (not None) and (not "<anything>") = True and False = False → 401 never returned After the bypass, set_auth_token() is never called (lines 283–291 only run when auth_token is truthy). The patched token getter at lines 163–168 resolves get_auth_token() = None, then delegates to original_get_current_access_token(). The

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