x402 SDKs · Disclosed

x402 Patches 25 SDK Flaws That Could Drain AI Agent Balances

Oct 21, 2026 · 1 min read

A V12 audit found 25 vulnerabilities in the x402 payment protocol SDKs for TypeScript, Python, and Go. Flaws such as the missing default spending limit could let malicious APIs drain AI agents' token balances. Fixes are available: update @x402/* packages to 2.23.0 or later, Python to 2.25.0, and Go to v2.28.0.

By HIFY Radar newsroom Updated 10/26/2026 01:17 PM Get this every day →← Back to the feed 2 sources

HighVulnerabilityDisclosedPatched

In this article

What happened
Why it matters
What to do
For the technical team
Timeline
Sources

What happened

An audit by security firm V12 found 25 vulnerabilities in the x402 payment protocol SDKs for TypeScript, Python, and Go. Flaws such as the missing default spending limit could let malicious APIs drain AI agents' token balances. Fixes have already been released.

Why it matters

Companies using x402 for AI agents to pay for services risked losing token balances to malicious APIs. The flaws affect core payment components: request wrappers (fetch/axios), Solana payments, and SIWx login signing.

What to do

Update @x402/fetch, @x402/axios, @x402/extensions, and @x402/svm to 2.23.0 or later, the Python x402 package to 2.25.0, and the Go module to v2.28.0. Review agent balances and payment history.

For the technical team

Affected: x402 SDKs (TypeScript @x402/*, Python x402, Go) · @x402/svm 2.0.0 to 2.22.0; @x402/fetch and @x402/axios before 2.23.0; @x402/extensions before 2.23.0; Python and Go clients before the August 18, 2026 releases (no spending limit, SIWx check).
Exploitation: Sources report no active exploitation or public PoC. Flaws were disclosed after fixes were released.
Fix: @x402/fetch, @x402/axios, @x402/extensions, and @x402/svm 2.23.0 or later (latest 2.28.0); x402 on PyPI 2.25.0 (latest); Go module v2.28.0 (latest).
Vector: x402 payment protocol SDKs. Three critical findings: no default spending limit in @x402/fetch and @x402/axios (and in the Python and Go clients), Solana approval accepted as payment in @x402/svm, and SIWx signing logins for other sites in @x402/extensions. Per The Hacker News, malicious APIs could drain agents' token balances.
More details: V12 audit, detailed 2026-10-26; V12 lists start as 2026-10-22 and rates severity critical. The V12 post details three critical findings among the 25 flaws. The Hacker News covered the case. Python and Go clients were fixed in the August 18, 2026 releases.