Browser — the complete, unedited output of the deterministic mcptrustchecker engine v1.13.0, scanned . Every finding, capability tag and score component below is exactly what the engine produced — no AI, no post-processing.
{
"tool": {
"name": "mcptrustchecker",
"version": "1.13.0",
"methodologyVersion": "mcptrustchecker-1.13"
},
"target": {
"id": "@fusengine/browser-mcp",
"source": {
"kind": "package",
"origin": "@fusengine/browser-mcp"
},
"server": {
"name": "@fusengine/browser-mcp"
}
},
"grade": "A",
"score": {
"score": 93,
"threatScore": 99,
"grade": "A",
"band": "A",
"categorySubtotals": {
"injection": 0,
"exfiltration": 0,
"permissions": 0,
"supply-chain": 1.2,
"network": 0,
"hygiene": 0
},
"vector": [
{
"kind": "threat",
"ruleId": "MTC-SUP-010",
"category": "supply-chain",
"severity": "low",
"confidence": "heuristic",
"rawWeight": 3,
"confidenceMult": 0.4,
"diminishingFactor": 1,
"appliedPenalty": 1.2
},
{
"kind": "client",
"term": "capability-exposure",
"level": "high",
"label": "capability blast radius (high) — client exposure if the model is manipulated",
"appliedPenalty": 6
},
{
"kind": "client",
"term": "verification-discount",
"level": "source",
"label": "publisher verification (provenance) — cryptographic build provenance ties the artifact to its source",
"appliedPenalty": 0
},
{
"kind": "client",
"term": "coverage-honesty",
"level": "source",
"label": "inspection depth (source) — how much of the target the scan could see",
"appliedPenalty": 0
}
],
"gatesFired": [],
"methodologyVersion": "mcptrustchecker-1.13"
},
"capability": {
"level": "high",
"reasons": [
"ingests untrusted external content (a prompt-injection entry point)",
"can execute shell commands or code"
],
"tags": [
"untrusted-input",
"code-exec"
]
},
"coverage": {
"level": "source",
"inputs": {
"toolSurface": true,
"implementationSource": true,
"packageMetadata": true,
"liveTransport": false
},
"caveats": [
"Tools were statically extracted from the published source (41 recovered), not enumerated from a running server. Tool-poisoning, Unicode-smuggling, capability and toxic-flow analysis ran on this inferred surface, but a mis-parsed registration could be missed or mis-attributed, so tool-derived findings are capped below “confirmed”. To grade the real runtime surface, scan the running server: --command \"npx -y <package>\"."
]
},
"findings": [
{
"ruleId": "MTC-SRC-002",
"title": "Shell/command execution in server code (dist/engine/cdp-launch.js)",
"category": "permissions",
"severity": "high",
"confidence": "strong",
"description": "In the server's implementation (`dist/engine/cdp-launch.js:12`): 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.",
"remediation": "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": {
"kind": "server",
"name": "dist/engine/cdp-launch.js"
},
"evidence": "rt { spawn } from \"node:child_process\"; import { logger } from \"../lib/logger.js\"; /** * Spawn a browser binary with re",
"owasp": "LLM05:2025 Improper Output Handling",
"data": {
"rule": "MTC-SRC-002",
"file": "dist/engine/cdp-launch.js",
"line": 12,
"nonRuntime": false
}
},
{
"ruleId": "MTC-SRC-002",
"title": "Shell/command execution in server code (dist/live/open-url.js)",
"category": "permissions",
"severity": "high",
"confidence": "strong",
"description": "In the server's implementation (`dist/live/open-url.js:5`): 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.",
"remediation": "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": {
"kind": "server",
"name": "dist/live/open-url.js"
},
"evidence": "rt { spawn } from \"node:child_process\"; /** Spawn the platform opener for `url`, detached; failures are ignored. */ expo",
"owasp": "LLM05:2025 Improper Output Handling",
"data": {
"rule": "MTC-SRC-002",
"file": "dist/live/open-url.js",
"line": 5,
"nonRuntime": false
}
},
{
"ruleId": "MTC-SRC-002",
"title": "Shell/command execution in server code (dist/state/action-memory.js)",
"category": "permissions",
"severity": "high",
"confidence": "strong",
"description": "In the server's implementation (`dist/state/action-memory.js:9`): 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.",
"remediation": "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": {
"kind": "server",
"name": "dist/state/action-memory.js"
},
"evidence": "f (!dir) return exec(action); const url = page.url(); const remembered = rememberedAction(loadSiteMemory",
"owasp": "LLM05:2025 Improper Output Handling",
"data": {
"rule": "MTC-SRC-002",
"file": "dist/state/action-memory.js",
"line": 9,
"nonRuntime": false
}
},
{
"ruleId": "MTC-CAP-007",
"title": "Unconstrained URL/host parameter \"url\" on \"browser_crawl\"",
"category": "network",
"severity": "medium",
"confidence": "heuristic",
"description": "Tool \"browser_crawl\" takes a URL/host parameter \"url\" with no allowlist/pattern. An outbound-request tool with an unbounded destination enables SSRF and cloud-metadata access (e.g. 169.254.169.254).",
"remediation": "Allowlist destinations or constrain the parameter; block private/link-local addresses server-side.",
"location": {
"kind": "tool",
"name": "browser_crawl",
"field": "inputSchema.properties.url"
},
"owasp": "LLM06:2025 Excessive Agency",
"data": {
"param": "url"
}
},
{
"ruleId": "MTC-CAP-007",
"title": "Unconstrained URL/host parameter \"url\" on \"browser_fetch\"",
"category": "network",
"severity": "medium",
"confidence": "heuristic",
"description": "Tool \"browser_fetch\" takes a URL/host parameter \"url\" with no allowlist/pattern. An outbound-request tool with an unbounded destination enables SSRF and cloud-metadata access (e.g. 169.254.169.254).",
"remediation": "Allowlist destinations or constrain the parameter; block private/link-local addresses server-side.",
"location": {
"kind": "tool",
"name": "browser_fetch",
"field": "inputSchema.properties.url"
},
"owasp": "LLM06:2025 Excessive Agency",
"data": {
"param": "url"
}
},
{
"ruleId": "MTC-CAP-007",
"title": "Unconstrained URL/host parameter \"url\" on \"browser_site_shots\"",
"category": "network",
"severity": "medium",
"confidence": "heuristic",
"description": "Tool \"browser_site_shots\" takes a URL/host parameter \"url\" with no allowlist/pattern. An outbound-request tool with an unbounded destination enables SSRF and cloud-metadata access (e.g. 169.254.169.254).",
"remediation": "Allowlist destinations or constrain the parameter; block private/link-local addresses server-side.",
"location": {
"kind": "tool",
"name": "browser_site_shots",
"field": "inputSchema.properties.url"
},
"owasp": "LLM06:2025 Excessive Agency",
"data": {
"param": "url"
}
},
{
"ruleId": "MTC-SRC-002",
"title": "Shell/command execution in packaging/dev tooling (scripts/postinstall.mjs)",
"category": "permissions",
"severity": "low",
"confidence": "heuristic",
"description": "In a packaging/dev/install script (shipped, but not the server runtime) (`scripts/postinstall.mjs:6`): 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.",
"remediation": "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": {
"kind": "server",
"name": "scripts/postinstall.mjs"
},
"evidence": "{ execSync } from \"node:child_process\"; const skip = process.env.PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD || process.env.FUSE",
"owasp": "LLM05:2025 Improper Output Handling",
"data": {
"rule": "MTC-SRC-002",
"file": "scripts/postinstall.mjs",
"line": 6,
"nonRuntime": true
}
},
{
"ruleId": "MTC-SUP-010",
"title": "Package runs install-time scripts (postinstall)",
"category": "supply-chain",
"severity": "low",
"confidence": "heuristic",
"description": "\"@fusengine/browser-mcp\" executes postinstall script(s) at install time. An install hook runs at install time; most are routine build/setup, but review what it does before trusting it.",
"remediation": "Review the scripts; install with --ignore-scripts where possible and vet what they do.",
"location": {
"kind": "package",
"name": "@fusengine/browser-mcp"
},
"evidence": "node scripts/postinstall.mjs",
"owasp": "LLM03:2025 Supply Chain",
"references": [
"https://github.com/ossf/package-analysis",
"https://owasp.org/www-project-top-10-ci-cd-security-risks/"
],
"data": {
"scripts": [
"postinstall"
]
}
}
],
"toxicFlows": [],
"capabilities": [
{
"tool": "browser_autoscroll",
"tags": [],
"reasons": {}
},
{
"tool": "browser_clipboard",
"tags": [],
"reasons": {}
},
{
"tool": "browser_collect_batch",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"crawl\""
]
}
},
{
"tool": "browser_collect",
"tags": [],
"reasons": {}
},
{
"tool": "browser_connect",
"tags": [],
"reasons": {}
},
{
"tool": "browser_cookies",
"tags": [],
"reasons": {}
},
{
"tool": "browser_crawl",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"crawl\""
]
}
},
{
"tool": "browser_dialog",
"tags": [],
"reasons": {}
},
{
"tool": "browser_downloads",
"tags": [],
"reasons": {}
},
{
"tool": "browser_extract_schema",
"tags": [],
"reasons": {}
},
{
"tool": "browser_extract",
"tags": [],
"reasons": {}
},
{
"tool": "browser_fetch_batch",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "browser_fetch",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "browser_handoff",
"tags": [],
"reasons": {}
},
{
"tool": "browser_inspect",
"tags": [],
"reasons": {}
},
{
"tool": "browser_live_view",
"tags": [],
"reasons": {}
},
{
"tool": "browser_live_view_stop",
"tags": [],
"reasons": {}
},
{
"tool": "browser_console",
"tags": [],
"reasons": {}
},
{
"tool": "browser_network",
"tags": [],
"reasons": {}
},
{
"tool": "browser_metrics",
"tags": [],
"reasons": {}
},
{
"tool": "browser_navigate",
"tags": [],
"reasons": {}
},
{
"tool": "browser_pdf",
"tags": [],
"reasons": {}
},
{
"tool": "browser_permissions",
"tags": [],
"reasons": {}
},
{
"tool": "browser_probe",
"tags": [],
"reasons": {}
},
{
"tool": "browser_probe_html",
"tags": [],
"reasons": {}
},
{
"tool": "browser_products",
"tags": [],
"reasons": {}
},
{
"tool": "browser_route",
"tags": [],
"reasons": {}
},
{
"tool": "browser_run",
"tags": [],
"reasons": {}
},
{
"tool": "browser_screenshot",
"tags": [],
"reasons": {}
},
{
"tool": "browser_serp_batch",
"tags": [],
"reasons": {}
},
{
"tool": "browser_open",
"tags": [],
"reasons": {}
},
{
"tool": "browser_status",
"tags": [],
"reasons": {}
},
{
"tool": "browser_close",
"tags": [],
"reasons": {}
},
{
"tool": "browser_shots_batch",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"fetch\""
]
}
},
{
"tool": "browser_site_shots",
"tags": [
"untrusted-input"
],
"reasons": {
"untrusted-input": [
"keyword \"crawl\""
]
}
},
{
"tool": "browser_snapshot",
"tags": [],
"reasons": {}
},
{
"tool": "browser_act",
"tags": [],
"reasons": {}
},
{
"tool": "browser_tabs",
"tags": [],
"reasons": {}
},
{
"tool": "browser_vault",
"tags": [],
"reasons": {}
},
{
"tool": "browser_visual_diff",
"tags": [],
"reasons": {}
},
{
"tool": "browser_wait_for",
"tags": [],
"reasons": {}
}
],
"surfaceDigest": "281fca3cc1f850604e674ce8bc212b18b09ddccdcd9c4602491d2aff78563599",
"stats": {
"tools": 41,
"prompts": 0,
"resources": 0,
"findingsBySeverity": {
"critical": 0,
"high": 3,
"medium": 3,
"low": 2,
"info": 0
}
}
}