“One forgotten eval() sank a fintech’s $2 M seed round. Let’s make sure it doesn’t happen to you.”

Nodejs makes shipping features fast; sometimes too fast. In 2025, public CVE data shows SQL/NoSQL injection is still the #1 flaw in Nodejs applications, followed closely by prototype pollution and malicious dependencies. Below you’ll find runnable code, real-world fixes, and a copy-paste checklist so you can push secure code without slowing CI/CD.

nodejs security checklist

Why Nodejs Apps Get Pwned in 2025

Dependency sprawl: the average Express project pulls 1 200+ packages.
Event-loop blocking: a single ReDoS regex can spin CPU to 100 %.
Typosquatting: packages like electorn (note the typo) still rack up 20 k weekly downloads before takedown.

The 7 Deadly Vulnerabilities & Code-Level Fixes

SQL/NoSQL Injection

Bad

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const query = `SELECT * FROM users WHERE id = ${req.params.id}`;

Good

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const text = 'SELECT * FROM users WHERE id = $1';
const values = [req.params.id];
await pool.query(text, values);

Use parameterized queries (pg, mysql2, mongodb all support them). Validate IDs with Joi.number().integer().positive().

Prototype Pollution

Vulnerable

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const _ = require('lodash');
_.merge({}, JSON.parse(req.body.json)); // user input

Fixed

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const cloned = structuredClone(JSON.parse(req.body.json)); // or
_.merge({}, JSON.parse(req.body.json), (objValue, srcValue) => {
  if (_.isObject(objValue) && objValue.constructor !== Object) return objValue;
});

Add Object.freeze(Object.prototype) during bootstrap to prevent prototype tampering.

XSS & CSRF

XSS fix

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const DOMPurify = require('isomorphic-dompurify');
const safeHTML = DOMPurify.sanitize(userInput);

CSRF fix

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const csrf = require('csurf');
app.use(csrf());

Send token in res.locals._csrf and validate on every state-changing request.

ReDoS & DoS

ReDoS-safe regex

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const safeRegex = require('safe-regex');
if (!safeRegex(userRegex)) throw new Error('Dangerous pattern');

Rate-limiting

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const rateLimit = require('express-rate-limit');
app.use('/login', rateLimit({ windowMs: 15 * 60 * 1000, max: 5 }));

Malicious Dependencies

  1. npm config set ignore-scripts true
  2. npx lockfile-lint --path package-lock.json --allowed-hosts npm
  3. npm audit --audit-level moderate in CI.

Sensitive Data Exposure

  • Store secrets in .env, never commit to Git.
  • Hash passwords with bcrypt.hash(password, 12).
  • Add Helmet in one line:
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const helmet = require('helmet');
app.use(helmet());

Headers added include Strict-Transport-Security, X-Content-Type-Options, Content-Security-Policy, etc.

SSRF & DNS Rebinding

Allow-list IPs

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const ip = require('ip');
if (!ip.cidrSubnet('10.0.0.0/8').contains(targetIP)) throw new Error('Forbidden');

Disable inspector in prod: node --inspect=0.0.0.0:0 is never safe.

Nodejs Security Checklist 2025 (Copy-Paste Ready)

# Task CLI / Snippet
1 Use Nodejs 20+ nvm use 20
2 Enable --experimental-permission node --experimental-permission --allow-fs-read=* index.js
3 Parameterize all queries pool.query('SELECT * FROM users WHERE id = $1', [id])
4 Freeze prototypes Object.freeze(Object.prototype)
5 Add Helmet app.use(helmet())
6 Rate-limit sensitive routes express-rate-limit
7 Audit deps npm audit --audit-level moderate
8 Lint lockfile npx lockfile-lint
9 Sanitize HTML DOMPurify.sanitize()
10 Hash passwords bcrypt.hash(password, 12)
11 Validate env require('dotenv-safe').config()
12 Secure CI npm ci --ignore-scripts

Save as SECURITY.md in repo root.

Tooling Deep-Dive

Tool Type Example
eslint-plugin-security Static linting npm i -D eslint-plugin-security "extends": ["plugin:security/recommended"]
Snyk Code SAST npx snyk test
CodeQL GitHub-native .github/workflows/codeql.yml

Helmet vs express-rate-limit

Concern Helmet express-rate-limit
XSS ✔ CSP header ✖
Brute-force login ✖ ✔
ReDoS mitigation ✖ ✔
Lines of code 1 3-5

Use both; they’re complementary.

Automating Security in CI/CD

.github/workflows/security.yml

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name: Security
on: [push]
jobs:
  audit:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 20
      - run: npm ci --ignore-scripts
      - run: npm audit --audit-level moderate
      - run: npx lockfile-lint --path package-lock.json

FAQ

Q: How to prevent SQL injection in Nodejs?
A: Always use parameterized queries ($1, $2 placeholders) and validate inputs with Joi or zod.

Q: Nodejs prototype pollution fix with example?
A: Freeze Object.prototype on startup and sanitize deep merges as shown above.

Q: Best Nodejs security linter?
A: eslint-plugin-security for quick local checks; Snyk Code or CodeQL for deeper SAST in CI.

Conclusion & Next Step

Security doesn’t have to be a drag. Add the checklist to your repo, drop Helmet & rate-limiting into your app today, and let CI fail builds that introduce new vulns.

Sources

  • OWASP Top 10 2021
  • Nodejs Security WG CVE Reports 2023-24
  • Snyk State of Open Source Security 2025

✨ Thank you for reading and I hope you find it helpful. I sincerely request for your feedback in the comment’s section.