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
Affected Vendors & Products
Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-h4mw-j7qp-8mwm | Claude Agent SDK: Argument Injection via resume Option Allows Arbitrary Command Execution |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Fri, 16 Oct 2026 20:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Claude Agent SDK: Argument Injection via resume Option Allows Arbitrary Command Execution | |
| Weaknesses | CWE-20 CWE-78 CWE-88 |
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| References |
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| Metrics |
cvssV4_0
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-10-16T19:44:01.260Z
Reserved: 2026-09-23T14:35:50.128Z
Link: CVE-2026-96620
No data.
Status : Received
Published: 2026-10-16T20:18:28.293
Modified: 2026-10-16T20:18:28.293
Link: CVE-2026-96620
No data.
OpenCVE Enrichment
Updated: 2026-10-16T22:00:16Z
Github GHSA