Grades are a hygiene check, not a security guarantee.

MCP, MCP server

io.github.Koala-Studios/newton-browser

Newton Browser is a local MCP browser-control product for agents.

Compatibility: Not stated.

Grade B

Minor issues only, no Medium or High. Worth a quick look at the findings below before installing.

Graded by PlugVetRubric v2

Not a guarantee. A hygiene check of the source at the commit shown, not a security audit.

Rescanned at commit e2cb84f6c21e, unchanged since the check below.

PERMISSION_DELETE_FILES NETWORK_NO_FIXED_HOST SECRETS_PATH_DOTENV SECRETS_ENV_READ OBFUSCATION_FILE_OVER_READ_CAP

Why this grade

  • PERMISSION_DELETE_FILES Low

    Contains a call that can delete files.

    apps/mcp-server/src/adapter-directory.ts, line 57 }finally{await fs.unlink(stage).catch(error=>{if(error.code!=='ENOENT')throw error;});}

  • NETWORK_NO_FIXED_HOST Low

    Makes a network call whose host is not written as a fixed address.

    apps/mcp-server/src/native-broker.ts, line 42 if(payload?.type==='response'&&(!Number.isSafeInteger(payload.id)||!requests.get(message.connectionId)?.delete(Number(payload.id)))){client.close();return;}

  • SECRETS_PATH_DOTENV Low

    Mentions a .env file.

    scripts/smoke/linux-chrome-live/prepare-workspace.mjs, line 97 return segment === ".env" || segment.startsWith(".env.") ||

  • SECRETS_ENV_READ Note

    Reads an environment variable whose name contains KEY, SECRET, TOKEN, PASSWORD or CREDENTIAL.

    scripts/verify-tab-foundation.mjs, line 102 spawn: (exe,args,options) => spawn(exe,[...args,...qaBrowserArgs,`--load-extension=${adapter}`],{...options,env:{...(options?.env??process.env),...homeEnv}}) });

  • OBFUSCATION_FILE_OVER_READ_CAP Note

    A file was over the read cap and was not fully read.

    test/evidence/bugs.md, line 1 # Newton Browser defect ledger

Any High, or two or more Medium findings, give D. One Medium gives C. Low findings or a security Note give B. Each code names a finding behind the letter.

Grades are a hygiene check of the source at the commit shown, on the date checked, not a security audit or a guarantee. The free directory grades are automated. Before release, a PlugVet engineer reviews every paid report and any grade we hold back, including all F grades, against the source code and the evidence we quote.

What was checked

Plain notes from the hygiene checks.

  • Permissions

    Concern

    can delete files.

    PERMISSION_DELETE_FILES

    apps/mcp-server/src/adapter-directory.ts, line 57

    }finally{await fs.unlink(stage).catch(error=>{if(error.code!=='ENOENT')throw error;});}

    apps/mcp-server/src/adapter-directory.ts, line 90

    for(const name of [...names,'installation.json'])await fs.unlink(path.join(stage,name)).catch(error=>{if(error.code!=='ENOENT')throw error;});

    apps/mcp-server/src/adapter-installation.ts, line 40

    }finally{await fs.unlink(filename).catch(error=>{if(error.code!=='ENOENT')throw error;});}

    Show more

    apps/mcp-server/src/adapter-update-journal.ts, line 45

    finally{await fs.unlink(stage).catch(error=>{if(error.code!=='ENOENT'){poisoned=true;throw error;}});}

    apps/mcp-server/src/config.ts, line 100

    fs.rmSync(displaced);

    apps/mcp-server/src/config.ts, line 105

    try { fs.rmSync(temporary, { force: true }); } catch { /* bounded caller error */ }

    apps/mcp-server/src/config.ts, line 108

    try { fs.rmSync(file); } catch { /* restoration attempted below */ }

    apps/mcp-server/src/install.ts, line 184

    fs.rmSync(directory.path, { recursive: true });

  • Install and update

    Pass

    No install-time script found, and dependencies are pinned or absent.

  • Network

    Concern

    can reach a host that is not written as a fixed address.

    NETWORK_NO_FIXED_HOST

    apps/mcp-server/src/native-broker.ts, line 42

    if(payload?.type==='response'&&(!Number.isSafeInteger(payload.id)||!requests.get(message.connectionId)?.delete(Number(payload.id)))){client.close();return;}

    apps/mcp-server/src/native-broker.ts, line 50

    clearTimeout(timer);connections.delete(connectionId);requests.delete(connectionId);

    apps/mcp-server/src/native-client.ts, line 29

    const socket=net.connect(endpoint),controller=new AbortController();

    Show more

    apps/mcp-server/src/browser-runtime/egress-proxy.ts, line 42

    const upstream = net.connect({ host: address, port: Number(match![2]) });

    apps/mcp-server/src/browser-runtime/egress-proxy.ts, line 62

    const upstream = http.request({ host: address, port, method: request.method, path: url.pathname + url.search, headers }, reply => {

    apps/tab-adapter/src/worker.ts, line 33

    o.subtle.digest("SHA-256", await (await fetch(chrome.runtime.getURL("worker.js"))).arr

    scripts/verify-engine-foundation.mjs, line 20

    ')?"<script>addEventListener('load',()=>fetch('/cross-ready'))</script>":''}`);return;

    scripts/verify-engine-foundation.mjs, line 24

    abel>Normal <input id="normal" oninput="fetch('/saved',{method:'POST',body:this.value}

  • Secrets

    Concern

    reads a credential or environment file.

    SECRETS_ENV_READ SECRETS_PATH_DOTENV

    apps/mcp-server/src/browser-runtime/setup-cli.ts, line 42

    const engine = createBrowserEngine({ configDirectory: root, browserExecutable: executable, env: { ...env, NEWTON_BROWSER_EGRESS: undefined } });

    scripts/smoke/linux-chrome-live/prepare-workspace.mjs, line 97

    return segment === ".env" || segment.startsWith(".env.") ||

    scripts/verify-tab-foundation.mjs, line 102

    spawn: (exe,args,options) => spawn(exe,[...args,...qaBrowserArgs,`--load-extension=${adapter}`],{...options,env:{...(options?.env??process.env),...homeEnv}}) });

    Show more

    scripts/verify-tab-foundation.mjs, line 240

    spawn:(exe,args,options)=>spawn(exe,[...args,...qaBrowserArgs,`--load-extension=${adapter}`],{...options,env:{...(options?.env??process.env),...homeEnv}})});

  • Agent instructions

    Pass

    No instruction to ignore earlier instructions or to hide a step.

  • Obfuscation

    Note

    a file was over the read cap and was not fully read.

    OBFUSCATION_FILE_OVER_READ_CAP

    test/evidence/bugs.md, line 1

    # Newton Browser defect ledger

  • Licence

    Pass

    A licence file is present (LICENSE).

  • Maintainer activity

    Pass

    The latest commit is within the last 365 days.

Get the full report on this tool, £49

Note

Hygiene check of commit e2cb84f6c21e. can delete files. can reach a host that is not written as a fixed address. reads a credential or environment file. a file was over the read cap and was not fully read.

Date and source

Date checked:

View source

github.com

Commit graded: e2cb84f6c21eb5c1d854a25679d8e49899040580

This link goes to the original host. PlugVet does not host or check what you download from there, and installing it is your own decision and risk.

Read how this letter is chosen