Marimo Notebook Flaw Could Run MCP Commands Before Cells Execute in Edit Mode

Marimo has patched a high-severity code injection vulnerability, tracked as CVE-2026-75149, which permitted attackers to execute unauthorized Model Context Protocol (MCP) commands within their notebook software. The flaw, rated 8.7 on the CVSS v4 scale, affects versions prior to 0.23.15 and allows a crafted notebook to launch a local subprocess containing attacker-controlled data when opened in edit mode. This risk arises before any notebook cells are executed, effectively bypassing standard execution boundaries. Users are advised to upgrade immediately to version 0.23.15 or later to mitigate this threat.