CVE-2026-96620

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

Published 16 Oct 2026Modified 21 Oct 2026CWE 20, 78, 88

In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.

Severity by source

GHSA9.2CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Trivy's own label is CRITICAL. Rated critical by GHSA.

Description

Claude Agent SDK is a Python SDK for Claude Code. Prior to 0.2.121, the resume option is passed to the Claude CLI as a separate token without validation, so a dash-leading value is parsed as an independent CLI flag. An attacker can inject the --mcp-config flag to define a stdio MCP server, causing arbitrary command execution at CLI startup outside the SDK permission controls. The issue is exploitable when an application passes untrusted input as the session ID to resume. This issue is fixed in version 0.2.121.

Affected packages and fixed versions

Source	Package	Fixed in
pip::GitHub Security Advisory pip	claude-agent-sdk	0.2.121

References

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