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CVE-2026-96620 Details

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.

Metrics

CVSS 3.x Severity and Vector Strings:

No CVSS 3.x data is available for this CVE.

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://github.com/anthropics/claude-agent-sdk-python/commit/347a1cb88d7652199399db1b7f914e0a459a6662	[email protected]
https://github.com/anthropics/claude-agent-sdk-python/pull/1123	[email protected]
https://github.com/anthropics/claude-agent-sdk-python/releases/tag/v0.2.121	[email protected]
https://github.com/anthropics/claude-agent-sdk-python/security/advisories/GHSA-h4mw-j7qp-8mwm	[email protected]

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-20	Improper Input Validation	[email protected]
CWE-78	Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')	[email protected]
CWE-88	Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')	[email protected]

Affected Products

No affected product data is available for this CVE.

Change History

2 change records found show changes

Date	Action	Recorded By
Oct 21, 2026	CVE Modified	CISA-ADP
Oct 16, 2026	New CVE Received	[email protected]