Bolt
security
Insecure Cookie Configuration in Bolt Application
Your Bolt.new application stores authentication tokens or session data in cookies without proper security attributes. Missing HttpOnly, Secure, and SameSite flags leave your users' sessions vulnerable to theft through XSS attacks, man-in-the-middle interception, and cross-site request forgery.
When Bolt generates authentication code, it may set cookies using basic document.cookie assignments or use a cookie library with default (insecure) settings. This means session tokens can be read by JavaScript (enabling XSS-based theft), transmitted over unencrypted HTTP connections, and sent along with cross-site requests.
An attacker who steals a session cookie can impersonate any user on your platform, access their data, make purchases on their behalf, or escalate privileges to admin accounts. This is a silent vulnerability that leaves no trace until it's exploited.
Error Messages You Might See
Warning: Cookie set without HttpOnly flag
Cookie rejected due to SameSite=None without Secure
Set-Cookie header ignored: must be Secure when SameSite=None
Mixed Content: cookie will be blocked in future browser versions
Common Causes
- Missing HttpOnly flag — Cookies are readable by JavaScript via document.cookie, so any XSS vulnerability can steal session tokens
- Missing Secure flag — Cookies are sent over unencrypted HTTP connections, allowing interception on public WiFi networks
- SameSite not set to Strict or Lax — Cookies are sent with cross-site requests, enabling CSRF attacks
- Cookies set from client-side JavaScript — Using document.cookie or js-cookie instead of setting cookies from the server with proper flags
- Overly broad cookie domain or path — Cookies scoped to a parent domain or root path, making them accessible to other subdomains or paths that may be compromised
How to Fix It
- Set cookies from the server — Use Set-Cookie headers from your API routes instead of document.cookie: res.setHeader('Set-Cookie', `token=${value}; HttpOnly; Secure; SameSite=Lax; Path=/; Max-Age=86400`)
- Enable HttpOnly — This prevents JavaScript from accessing the cookie, blocking XSS-based theft entirely
- Enable Secure flag — Ensures cookies are only sent over HTTPS connections, preventing interception
- Set SameSite to Lax or Strict — Lax allows cookies on top-level navigations (links), Strict blocks all cross-site cookie sending
- Use a session library — Install iron-session or next-auth which handle secure cookie configuration by default
- Set proper expiration — Use Max-Age or Expires instead of session cookies for persistent login, and set reasonable timeouts
Real developers can help you.
Omar Faruk
As a Product Engineer at Klasio, I contributed to end-to-end product development, focusing on scalability, performance, and user experience.
My work spanned building and refining core features, developing dynamic website templates, integrating secure and reliable payment gateways, and optimizing the overall system architecture.
I played a key role in creating a scalable and maintainable platform to support educators and learners globally.
I'm enthusiastic about embracing new challenges and making meaningful contributions.
Rudra Bhikadiya
I build and fix web apps across Next.js, Node.js, and DBs.
Comfortable jumping into messy code, broken APIs, and mysterious bugs.
If your project works in theory but not in reality, I help close that gap.
rayush33
JavaScript (React.js, React Native, Node.js) Developer with demonstrated industry experience of 4+ years, actively looking for opportunities to hone my skills as well as help small-scale business owners with solutions to technical problems
Daniel Vázquez
Software Engineer with over 10 years of experience on Startups, Government, big tech industry & consulting.
David Olverson
Solo dev shipping production apps with AI-assisted development. I specialize in rescuing broken Lovable/Bolt/Cursor builds and taking them to production. 10+ apps shipped including SaaS CRMs, gaming platforms, real estate tools, and Discord bots. Stack: Next.js 16, TypeScript, Tailwind CSS, FastAPI, PostgreSQL, Prisma. I use Claude Code with 50+ custom skills for rapid delivery. Average turnaround: 2-4 weeks from broken prototype to production.
Kingsley Omage
Fullstack software engineer passionate about AI Agents, blockchain, LLMs.
Matt Butler
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Jacek Rozanski
Senior PHP/Symfony developer and DevOps engineer with 20+ years of professional experience, running opcode.pl (web development agency, est. 2004).
Day job: I'm the sole backend developer at merketing company where I own and maintain 11 PHP/Symfony microservices on AWS (ECS Fargate, RDS, S3, CloudFront), handle the full CI/CD pipeline (Bitbucket Pipelines, Docker), and manage monitoring with Sentry and CloudWatch. These services handle high request volumes in production every month.
What I bring to AI-built apps:
- I audit and fix security issues (OWASP methodology), performance bottlenecks, and architectural problems in codebases generated by Cursor, Claude Code, Lovable, Bolt, and v0
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Tech stack: PHP 8.x, Symfony, React, Next.js, PostgreSQL, MySQL, Docker, AWS (ECS, RDS, S3, SQS/SNS, CloudFront), Terraform, Supabase. I also use AI tools daily (Claude Code, Cursor) in my own workflow, so I understand both the strengths and the gaps in AI-generated code.
Based in Poland (CET timezone). Available for async work and calls during EU/US business hours.
Meïr Ankri
Full-stack developer specializing in React / Next.js / Node.js with 6+ years of experience. I've worked across various sectors including automotive (Reezocar/Société Générale), healthcare (Medical Link SaaS), and e-commerce (Glasman). I build web apps end-to-end, from architecture to production, with a focus on scalability, performance, and code quality. I also mentor junior developers and contribute to technical decisions and code reviews.
Vlad Temian
15+ years shipping production infrastructure for startups. Former CTO at qed.builders (acquired by The Sandbox).
Cursor ambassador and agentic tooling builder.
I've scaled systems, automated deployments, and built observability tools for AI coding workflows. I specialize in taking vibe-coded apps from broken prototype to production-ready: fixing Supabase auth/RLS, Stripe integrations, deployment pipelines, and cleaning up AI-generated spaghetti.
I build tools in this space (agentprobe, claudebin, micode) and understand both sides: how AI generates code and why it breaks.
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Get HelpFrequently Asked Questions
What is the difference between HttpOnly, Secure, and SameSite?
HttpOnly prevents JavaScript access to the cookie (blocks XSS theft). Secure ensures the cookie is only sent over HTTPS. SameSite controls whether cookies are sent with cross-site requests (blocks CSRF). You need all three for proper security.
Should I use localStorage or cookies for auth tokens?
Cookies with HttpOnly and Secure flags are safer for auth tokens because JavaScript cannot access them, making XSS attacks ineffective. localStorage is readable by any script on the page, so a single XSS vulnerability exposes all tokens.