{"cve":"CVE-2026-96620","nvd":{"published":"2026-10-16T20:18:28.293","modified":"2026-10-21T22:16:50.597","status":"Awaiting Analysis","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.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","score":9.2},"cvss_v3":null,"cwes":["CWE-20","CWE-78","CWE-88"],"references":["https://github.com/anthropics/claude-agent-sdk-python/commit/347a1cb88d7652199399db1b7f914e0a459a6662","https://github.com/anthropics/claude-agent-sdk-python/pull/1123","https://github.com/anthropics/claude-agent-sdk-python/releases/tag/v0.2.121","https://github.com/anthropics/claude-agent-sdk-python/security/advisories/GHSA-h4mw-j7qp-8mwm"],"products":[],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-96620","score":0.00705,"percentile":0.53084,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-h4mw-j7qp-8mwm","url":"https://osv.dev/vulnerability/GHSA-h4mw-j7qp-8mwm","summary":"Claude Agent SDK: Argument Injection via resume Option Allows Arbitrary Command Execution","modified":"2026-10-16T20:00:04.101685566Z","packages":[{"ecosystem":"PyPI","name":"claude-agent-sdk","purl":"pkg:pypi/claude-agent-sdk","ranges":["<0.2.121"],"fixed":["0.2.121"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}