A critical vulnerability has been discovered in the Marimo open-source Python notebook tool, which is used for data science, analysis, and interactive coding. The bug, tracked as CVE-2026-39987, has a CVSS score of 9.3 and affects versions up to 0.20.4. This vulnerability allows pre-authenticated remote code execution, enabling an attacker to obtain a full PTY shell and execute arbitrary system commands. The Marimo tool has approximately 20,000 GitHub stars, making it a relatively niche tool. Ho...