CVE Catalog

CVE-2026-96620

CriticalCVSS 9.2
Published: Translated: NVD NIST

Summary

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.

Risk Assessment

The issue is exploitable when an application passes untrusted input as the session ID to resume, potentially leading to arbitrary command execution.

Recommendation

Update Claude Agent SDK to version 0.2.121 or later.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS