T09 · Insecure Skill Coding Practices
Error
- Location
x402_cli.py:212- Finding
Automatic Payment Proceeds When Local Spending-Limit Validation Is Incomplete
- Content
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max_payment: raise Exception( f"Payment ${max_amount_usd:.2f} exceeds limit ${max_payment:.2f}. " f"Use --max to increase." ) except (json.JSONDecodeError, KeyError, ValueError, IndexError): pass # Can't parse payment info, let x402 SDK handle it # Use v2 SDK — handles 402 payment automatically httpx_client = _get_x402_httpx_client() ``` ### Technical Analysis The local payment-limit check is not fail-closed. Validation only examines the first element of the response body's `accepts` array and assumes that `maxAmountRequired` is expressed in six-decimal USDC atomic units. If the payment requirements are malformed, header-only, use an unexpected schema, contain an invalid amount, or otherwise raise one of the caught parsing exceptions, the code suppresses the error and proceeds to create an x402-enabled client. That client has access to a signer backed by the operator's private key and automatically handles the payment. The code also does not demonstrate that the validated `accepts[0]` option is the same payment option ultimately selected by the SDK. Consequently, validating only the first option does not reliably constrain the transaction selected by the payment implementation. Additionally, this expression does not treat zero as an explicit limit: ```python max_payment = max_usd or _config["max_payment_usd"] ` ...[truncated 2104 chars]- Remediation
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