Unreal Engine (FFZackFair92) MCP Server

unreal-engine-mcp PyPI v0.10.0

Published by ffzackfair92 — no publish provenance, so origin is unverified, but the source is public: the repository link below is self-declared yet readable, so you can inspect the code before adopting it.

Drive Unreal Engine 5 from an AI agent: Remote Control API + in-editor Python, no C++ plugin to compile

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Trust grade

89/100

Last scanned 2026-08-25 get badge →

Trust

B · 89/100

Adoption risk for you: the threat score, then adjusted down for blast radius, publisher verification and how much the scan could see. Deterministic; every point is auditable.

Capability

Critical

Blast radius if it went rogue — what the server’s tools could reach. Independent of trust.

Coverage

Source

How much the scan could actually inspect. Shallow coverage is stated, never hidden.

B Why this grade threat 100 − adoption risk = 89/100

The grade answers one question — how safe is this server for you to adopt — so it is computed in two auditable stages. Nothing below is an opinion or an LLM's guess; every line is a real term the deterministic engine applied, and the same input always yields the same number.

1. Threat score — 100 − 0 = 100. What the published surface and source actually contain:

The deterministic scan raised no scored threat in the surface it inspected — the threat score stayed at 100. Capability observations and advisory notes are recorded but never lower it.

2. Client adoption risk — 100 − 11 = 89. Three small, subtract-only factors that reflect your risk in adopting it — a clean scan proves less on a powerful, unverified or barely-inspectable package, so the grade says so plainly:

Points	Adoption-risk factor
−10	capability blast radius (critical) — client exposure if the model is manipulated
−1	publisher verification (public source) — no provenance, but the source is public and inspectable

Capability observations and info notes are shown under Findings but never scored. Open any row's finding below for the file, line and evidence behind a deduction.

Findings 19

critical Completed toxic-flow trifecta across toolsMTC-FLOW-002

This server (without client built-ins) exposes a complete data-exfiltration chain: preset_download_ambientcg → ue_bt_info → ue_exec_python. Untrusted input is ingested, private data is read, and it can be sent to an external sink via the agent composing the tools (→). Static analysis proves the primitive exists, not that a specific run will occur.

Fix: Remove one leg of the trifecta: isolate untrusted-input tools from secret-reading tools and from egress tools, or require human approval between them.

Location: flow preset_download_ambientcg → ue_bt_info → ue_exec_python

high Tool "ue_exec_python" exposes command/code executionMTC-CAP-001

Tool "ue_exec_python" appears to run shell commands or evaluate code (keyword "exec" in tool name). Arbitrary execution driven by model input is one of the most dangerous MCP capabilities; combined with any untrusted input it becomes RCE.

Fix: Sandbox execution, allowlist commands/arguments, and never pass model output to a shell unescaped.

Location: tool ue_exec_python

high Tool "ue_spawn_actor" exposes command/code executionMTC-CAP-001

Tool "ue_spawn_actor" appears to run shell commands or evaluate code (keyword "spawn" in tool name). Arbitrary execution driven by model input is one of the most dangerous MCP capabilities; combined with any untrusted input it becomes RCE.

Fix: Sandbox execution, allowlist commands/arguments, and never pass model output to a shell unescaped.

Location: tool ue_spawn_actor

high Tool "ue_spawn_many" exposes command/code executionMTC-CAP-001

Tool "ue_spawn_many" appears to run shell commands or evaluate code (keyword "spawn" in tool name). Arbitrary execution driven by model input is one of the most dangerous MCP capabilities; combined with any untrusted input it becomes RCE.

Fix: Sandbox execution, allowlist commands/arguments, and never pass model output to a shell unescaped.

Location: tool ue_spawn_many

high Tool "ue_pcg_spawn_volume" exposes command/code executionMTC-CAP-001

Tool "ue_pcg_spawn_volume" appears to run shell commands or evaluate code (keyword "spawn" in tool name). Arbitrary execution driven by model input is one of the most dangerous MCP capabilities; combined with any untrusted input it becomes RCE.

Fix: Sandbox execution, allowlist commands/arguments, and never pass model output to a shell unescaped.

Location: tool ue_pcg_spawn_volume

high Tool "ue_foliage_spawn_volume" exposes command/code executionMTC-CAP-001

Tool "ue_foliage_spawn_volume" appears to run shell commands or evaluate code (keyword "spawn" in tool name). Arbitrary execution driven by model input is one of the most dangerous MCP capabilities; combined with any untrusted input it becomes RCE.

Fix: Sandbox execution, allowlist commands/arguments, and never pass model output to a shell unescaped.

Location: tool ue_foliage_spawn_volume

high Dynamic code execution in server code (src/unreal_mcp/bridge.py)MTC-SRC-001

In the server's implementation (`src/unreal_mcp/bridge.py:136`): Evaluating strings as code is the most direct RCE primitive; if any tool input reaches it, the server executes attacker-chosen code. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: ype({HELPERS_MODULE!r}) exec(compile({source!r}, "<unreal-mcp-helpers>", "exec"), _mcp_module.__dict__) _mcp_module.MCP_

Fix: Review this call path: confirm it never receives unsanitized tool input, constrain it, or remove it. Treat a server whose code reaches these sinks as high-capability regardless of what its tools claim.

Location: server src/unreal_mcp/bridge.py

high Shell/command execution in server code (src/unreal_mcp/assets.py)MTC-SRC-002

In the server's implementation (`src/unreal_mcp/assets.py:397`): Spawning a shell/process is command-execution capability; with unsanitized tool input it is command injection / RCE. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: ) result = subprocess.run( # noqa: S603 [executable, *args], capture_output=True, text=True, timeo

Location: server src/unreal_mcp/assets.py

high Shell/command execution in server code (src/unreal_mcp/bridge.py)MTC-SRC-002

In the server's implementation (`src/unreal_mcp/bridge.py:136`): Spawning a shell/process is command-execution capability; with unsanitized tool input it is command injection / RCE. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: ype({HELPERS_MODULE!r}) exec(compile({source!r}, "<unreal-mcp-helpers>", "exec"), _mcp_module.__dict__) _mcp_module.MCP_

Location: server src/unreal_mcp/bridge.py

high Shell/command execution in server code (src/unreal_mcp/local.py)MTC-SRC-002

In the server's implementation (`src/unreal_mcp/local.py:1302`): Spawning a shell/process is command-execution capability; with unsanitized tool input it is command injection / RCE. This is read from the code itself — not from the tool description — so a poisoned server cannot hide it behind honest-looking metadata.

Evidence: _PROCESS process = subprocess.Popen(args, **kwargs) # noqa: S603 state = { "pid": process.pid,

Location: server src/unreal_mcp/local.py

low Mutating tool "ue_exec_python" declares no destructiveHintMTC-CAP-005

Tool "ue_exec_python" can mutate/egress but declares no destructiveHint. Clients that don't default to spec-safe behavior may not prompt before running it.