# CVE-2026-105789: Microsoft UFO: Arbitrary file write in the Linux MCP `execute_command` tool

> An authenticated attacker can overwrite arbitrary files via the Linux MCP execute_command tool, potentially corrupting data or disrupting the service.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 6 Oct 2026
- **Updated:** 6 Oct 2026
- **Also known as:** GHSA-85w2-wggf-rw49

## What is CVE-2026-105789?

CVE-2026-105789 is a medium-severity path traversal vulnerability in microsoft UFO, published on 6 Oct 2026. Any signed-in user can exploit it over the network, 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 execute_command tool in ufo/client/mcp/http_servers/linux_mcp_server.py treats sort and uniq as read-only commands while the free-form command parameter can select their file-output forms. An authenticated caller can use sort -o or the optional second uniq operand to create or overwrite files writable by the UFO server process without shell metacharacters, because the allowed binary opens the destination itself and the argument policy does not reject the operation. This can corrupt configuration or other writable data and disrupt the service, but the demonstrated primitive does not directly disclose files or establish arbitrary code execution. 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-2026-105789?


## How do I fix CVE-2026-105789?

No fix has been published for CVE-2026-105789 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-105789 being exploited?

There is no known exploitation of CVE-2026-105789 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-105789 and fix it if it is affected.

What it is: CVE-2026-105789 is a medium-severity path traversal vulnerability in microsoft UFO, published on 6 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-105789 in the wild and no public exploit code.

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-2026-105789/ (Markdown: https://insights.sbomify.com/CVE-2026-105789/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-105789
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-105789
- OSV: https://osv.dev/vulnerability/CVE-2026-105789

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-105789/
Summaries are generated and may contain mistakes; the official description above is the record.