PYSEC-2026-559
Upsonic: remote code execution vulnerability in its MCP server/task creation functionality
Quick fix
PYSEC-2026-559 — upsonic: upgrade to the fixed version with the command below.
pip install --upgrade 'upsonic>=0.72.0'Details
Upsonic 0.71.6 contains a remote code execution vulnerability in its MCP server/task creation functionality. The application allows users to define MCP tasks with arbitrary command and args values. Although an allowlist exists, certain allowed commands (npm, npx) accept argument flags that enable execution of arbitrary OS commands. Maliciously crafted MCP tasks may lead to remote code execution with the privileges of the Upsonic process. In version 0.72.0 Upsonic added a warning about using Stdio servers being able to execute commands directly on the machine.
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Affected packages
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-30625[ADVISORY]
- https://github.com/Upsonic/Upsonic/commit/855053fce0662227d9246268ff4a0844b481a305[WEB]
- https://github.com/Upsonic/Upsonic[PACKAGE]
- https://www.ox.security/blog/mcp-supply-chain-advisory-rce-vulnerabilities-across-the-ai-ecosystem[WEB]
- https://pypi.org/project/upsonic[PACKAGE]
- https://github.com/advisories/GHSA-cw73-5f7h-m4gv[ADVISORY]