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CVE-2026-105789

Microsoft UFO: Arbitrary file write in the Linux MCP `execute_command` tool

5.4 Medium

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
Low
User interaction
Required

What an attacker can affect

Confidentiality
None
Integrity
High
Availability
Low

Exploit likelihood

0.70%Unchanged since Oct 7, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.4

Microsoft UFO: Arbitrary file write in the Linux MCP `execute_command` tool

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.

Record
CVE-2026-105789
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:L
Weakness
CWE-88, CWE-184
Updated
2026-11-02
EUVDEUVD-2026-93406 5.4

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.

Record
EUVD-2026-93406
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:L
Updated
2026-11-02
NVD 5.4

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.

Record
CVE-2026-105789
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:L
Weakness
CWE-88, CWE-184
Updated
2026-11-02
OSV 5.4

Microsoft UFO: Arbitrary file write in the Linux MCP `execute_command` tool

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.

Record
CVE-2026-105789
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:L
Weakness
CWE-184, CWE-88
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
first indexedCVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-105789 is a medium vulnerability (CVSS 5.4) in Microsoft Ufo, published October 6, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.70%, the 53rd percentile. No source names a fixed version.

References

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