Microsoft UFO: Arbitrary code execution in `run_shell` via `explorer.exe` argument injection
CVE-2026-105791
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.
No Active Exploit Signals
CVSS Base Score
7.5
HIGH
Exploitability:1.7
Impact Score:5.9
Executive Threat Verdict
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Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
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Authentication
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Weaponization
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SSVC Action
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CISA BINDING OPERATIONAL DIRECTIVE (BOD 22-01)Mandatory Federal Remediation
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