CVE-2026-96620
Claude Agent SDK: Argument Injection via resume Option Allows Arbitrary Command Execution
CVSS Score
0.0
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-20 CWE-78 CWE-88 |
| Vendor | anthropics |
| Product | claude-agent-sdk-python |
| Published | Oct 16, 2026 |
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Affected Versions
anthropics / claude-agent-sdk-python
< 0.2.121
References
github.com: https://github.com/anthropics/claude-agent-sdk-python/security/advisories/GHSA-h4mw-j7qp-8mwm github.com: https://github.com/anthropics/claude-agent-sdk-python/pull/1123 github.com: https://github.com/anthropics/claude-agent-sdk-python/commit/347a1cb88d7652199399db1b7f914e0a459a6662 github.com: https://github.com/anthropics/claude-agent-sdk-python/releases/tag/v0.2.121