critical vulnerability

Claude Agent SDK: Argument Injection via resume Option Allows Arbitrary Command Execution

Fix availableCritical · CVSS 9.2EPSS 0.58%

Published Oct 16, 2026 · updated Oct 16, 2026

What to do

Upgrade to a fixed version: claude-agent-sdk 0.2.121.
Redeploy and restart long-running processes so they load the fixed code.

Affected packages

PyPIclaude-agent-sdk

Vulnerable versions: < 0.2.121
Fixed in: 0.2.121

Check your project: pip show claude-agent-sdk

What changed

Oct 16, 2026
Published in the GitHub Advisory Database as critical.

Sources

GitHub Advisory GHSA-h4mw-j7qp-8mwm
NVD CVE-2026-96620

CWE-20 Improper Input Validation · CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') · CWE-88 Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')

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