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

Aug 25, 2026

Marimo has addressed a high-severity security flaw in its notebook software that allowed an attacker to execute an attacker-supplied Model Context Protocol (MCP) command in a specially crafted notebook, according to VulnCheck’s CVE Numbering Authority (CNA) record.

The CNA record says the command can run as a local subprocess when the notebook is opened in edit mode.

The vulnerability, tracked

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