Marimo Notebook Flaw Could Run MCP Commands Before Cells Execute in Edit Mode
Marimo notebook flaw CVE-2026-75149 (CVSS 8.7) allows attacker-supplied MCP commands to run as local subprocesses before any cell executes in edit mode.
Marimo addressed CVE-2026-75149, a high-severity code injection flaw allowing attacker-supplied Model Context Protocol (MCP) commands to execute as local subprocesses when a crafted notebook is opened in edit mode, before any cell runs. The issue affects versions prior to 0.23.15, carries CVSS v4 of 8.7 and CVSS v3.1 of 8.8, and requires user interaction but no authentication. Marimo fixed it in version 0.23.15 (released July 23, 2026) via a PEP 723 hardening patch that treats notebook metadata as attacker-controlled and strips ai, mcp, completion, secrets, and server configuration sections. VulnCheck's CNA also disclosed CVE-2026-67618 (CVSS 7.1), involving an attacker-controlled AI base_url that exfiltrates operator API keys, and earlier CVE-2023-39987, a missing auth on /terminal/ws endpoint allowing full PTY shell access.