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Response snapshot Oct 26, 2026, 22:09 UTC

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Vulnerabilitythehackernews-critical-x402-sdk-flaw-could-let-43513002b0c3

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

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.

At a glance

Exploited
Not known
Severity
Not scored yet
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory linked from the article for affected versions and fixes.

Read The Hacker News: Critical x402 SDK Flaw Could Let Malicious APIs Drain AI Agents’ Token Balances (opens a new tab)

What happened

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

Sources

  1. Reporting

    The Hacker News: Critical x402 SDK Flaw Could Let Malicious APIs Drain AI Agents’ Token Balances (opens a new tab)

    The article reports this vulnerability. It is reporting, not independently primary-confirmed or locally reviewed.

    Published Checked

  2. Reporting

    The Hacker News syndication feed (opens a new tab)

    The RSS/Atom/RDF entry supplied this exact link and any available title, date, and excerpt.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 23). Critical x402 SDK Flaw Could Let Malicious APIs Drain AI Agents’ Token Balances. https://kevwire.com/record/thehackernews-critical-x402-sdk-flaw-could-let-43513002b0c3

MLA

"Critical x402 SDK Flaw Could Let Malicious APIs Drain AI Agents’ Token Balances." KEVWire, 23 Oct. 2026, kevwire.com/record/thehackernews-critical-x402-sdk-flaw-could-let-43513002b0c3.

Chicago

KEVWire. "Critical x402 SDK Flaw Could Let Malicious APIs Drain AI Agents’ Token Balances." Last modified October 23, 2026. https://kevwire.com/record/thehackernews-critical-x402-sdk-flaw-could-let-43513002b0c3.

Evidence summary (plain text)

Critical x402 SDK Flaw Could Let Malicious APIs Drain AI Agents’ Token Balances (Oct 23, 2026).
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
Sources:
The Hacker News: Critical x402 SDK Flaw Could Let Malicious APIs Drain AI Agents’ Token Balances: https://thehackernews.com/2026/10/critical-x402-sdk-flaw-could-let.html
The Hacker News syndication feed: https://feeds.feedburner.com/TheHackersNews
Record ID: thehackernews-critical-x402-sdk-flaw-could-let-43513002b0c3.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 26, 2026, 22:05 UTC. Ingestion is not an independent editorial investigation.

Syndicated reporting, unreviewed by KEVWire and not independently primary-confirmed. Consult the exact article and any primary disclosure it links.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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