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Critical x402 SDK Flaw Could Let Malicious APIs Drain AI Agents’ Token Balances

·Source: The Hacker News

Updated:

Executive Summary

AI agents paying for API calls with the x402 SDKs could sign a payment for their full balance of a supported token if a malicious API asked for it, security firm V12 said on October 22. The cause was the SDKs' default client, which set no spending limit until releases on August 18 added one. The risk was limited to agents who automatically signed payments and whose apps set

Analysis

AI agents paying for API calls with the x402 SDKs could sign a payment for their full balance of a supported token if a malicious API asked for it, security firm V12 said on October 22. The cause was the SDKs' default client, which set no spending limit until releases on August 18 added one. The risk was limited to agents who automatically signed payments and whose apps set
Source Attribution

Originally published by The Hacker News on Oct 23, 2026.

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