Security audit
x402-budget-manager
Security checks for vulnerabilities and agentic risk
Overview
This is a disclosed budgeting guide for limiting x402 API spending, with no bundled executable code or hidden behavior found.
Review the configured caps before using this with any x402 client, because calls within the configured budget may proceed. Keep spend-log.json private since it can contain payment metadata, and prefer the documented pre-authorized limits so the agent cannot raise its own spending ceiling during a run.
Vulnerability Patterns
- Skill Instruction HijackingAlters the agent's session goals or safety constraints when the skill loads
- Agent Memory PoisoningWrites attacker-controlled rules into memory that affect later sessions
- Remote Payload Retrieval and ExecutionFetches external code whose behavior can change after review
- Embedded Malicious CodeShips malicious scripts inside the skill and executes them locally
- Unauthorized Access and Privilege EscalationObtains permissions beyond the task's legitimate needs
Vulnerability Patterns
- Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
- Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
- Privilege EscalationExcessive Permissions, Sudo/Root Execution, Credential Access
- Supply ChainUnpinned Dependencies, External Script Fetching, Obfuscated Code
- Excessive AgencyUnrestricted Tool Access, Autonomous Decision Making, Scope Creep