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

> Attackers can execute arbitrary code via argument injection in the run_shell tool, compromising user files and sessions in Microsoft UFO.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 6 Oct 2026
- **Updated:** 9 Oct 2026
- **Also known as:** GHSA-cmq9-vqjf-4q2q

## What is CVE-2026-105791?

CVE-2026-105791 is a high-severity command injection vulnerability in microsoft UFO, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-88 (Improper Neutralization of Argument Delimiters in a Command), CWE-184 (Incomplete List of Disallowed Inputs)

## Which versions are affected by CVE-2026-105791?


## How do I fix CVE-2026-105791?

No fix has been published for CVE-2026-105791 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-105791 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-105791 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-105791 and fix it if it is affected.

What it is: CVE-2026-105791 is a high-severity command injection vulnerability in microsoft UFO, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-105791 exists.

Affected product: microsoft UFO. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-105791/ (Markdown: https://insights.sbomify.com/CVE-2026-105791/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-105791
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-105791
- OSV: https://osv.dev/vulnerability/CVE-2026-105791

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-105791/
Summaries are generated and may contain mistakes; the official description above is the record.