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.
- 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
- None listed
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.
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.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-105791 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-105791 exists.
Sources
Also known as GHSA-cmq9-vqjf-4q2q.