On October 22, security firm V12 reported a critical flaw in the x402 SDKs that could allow AI agents to drain their full token balance if a malicious API requested it.
The vulnerability or weakness
The vulnerability was in the default client of the x402 SDKs, which set no spending limit until August 18 updates added one.
Earlier attacks and coverage
- OpenCode Flaw Lets Malicious MCP Servers Execute Code During Sign-In on Windows and WSL (2026-10-22)
- LiteLLM Suspects GitHub Token Leak in AI Gateway Logs Behind Malicious Package Release (2026-10-22) - The Hacker News
- Critical GitLab Flaw (CVSS 10.0) Could Allow Unauthenticated RCE Across 12 Years of Releases (2026-10-21)
- Critical FortiSIEM Flaw Gets Public Exploit PoC for Unauthenticated Remote Code Execution (2026-10-20)
- Researchers Warn OpenCode Quietly Patched Critical RCE Flaw, Leaving Users At Risk (2026-10-20)
Business impact
Organizations using AI agents with the x402 SDKs could face financial loss if attackers exploit this flaw to drain token balances.
Industries affected
Tech and finance industries, particularly those relying on AI agents for API calls, are affected.
Users affected
Users of AI agents that automatically sign payments and whose applications do not set spending limits are at risk.
