Bolt
security
Missing Input Sanitization in Bolt App Forms
Your Bolt.new application accepts user input from forms, URL parameters, and API requests without validating or sanitizing it. This leaves your app vulnerable to cross-site scripting (XSS), HTML injection, data corruption, and other attacks that exploit unfiltered input.
When Bolt generates form handling code, it often passes user input directly to the database or renders it on the page without checking for malicious content. A user could submit a script tag in a comment field, an extremely long string that breaks your layout, or special characters that corrupt your data.
The consequences range from cosmetic issues (broken layouts) to critical security breaches (stolen user sessions, defaced pages, or unauthorized data access). This is one of the most common security gaps in AI-generated applications.
Error Messages You Might See
Warning: Each child in a list should have a unique key prop
Content Security Policy violation: inline script blocked
Unhandled Runtime Error: Objects are not valid as a React child
XSS payload detected in input field
Common Causes
- No server-side validation — Form data is accepted and stored without checking type, length, or format on the backend
- Using dangerouslySetInnerHTML — Bolt generated React components that render user content as raw HTML, enabling XSS
- Client-only validation — Validation exists in the form component but not in the API route, so it can be bypassed with a direct API call
- No Content Security Policy — Missing CSP headers allow injected scripts to execute freely
- Rich text editors without sanitization — WYSIWYG editors that save and display raw HTML from users
- URL parameters used directly — Query string values rendered on the page without escaping
How to Fix It
- Add server-side validation with Zod — Define strict schemas: const schema = z.object({ name: z.string().min(1).max(100), email: z.string().email() }); and validate every API input
- Never use dangerouslySetInnerHTML with user data — Replace it with regular JSX text rendering: {userComment} instead of dangerouslySetInnerHTML={{__html: userComment}}
- Install DOMPurify for HTML content — If you must render HTML, sanitize it: DOMPurify.sanitize(htmlContent, { ALLOWED_TAGS: ['p', 'b', 'i', 'a'] })
- Add Content-Security-Policy headers — Configure CSP to block inline scripts: Content-Security-Policy: default-src 'self'; script-src 'self'
- Validate on both client and server — Share Zod schemas between frontend forms and backend API routes for consistent validation
Real developers can help you.
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.
https://blog.vtemian.com/
Luca Liberati
I work on monoliths and microservices, backends and frontends, manage K8s clusters and love to design apps architecture
Caio Rodrigues
I'm a full-stack developer focused on building practical and scalable web applications. My main experience is with **React, TypeScript, and modern frontend architectures**, where I prioritize clean code, component reusability, and maintainable project structures.
I have strong experience working with **dynamic forms, state management (Redux / React Hook Form), and complex data-driven interfaces**. I enjoy solving real-world problems by turning ideas into reliable software that companies can actually use in their daily operations.
Beyond coding, I care about **software quality and architecture**, following best practices for componentization, code organization, and performance optimization.
I'm also comfortable working across the stack when needed, integrating APIs, handling business logic, and helping transform prototypes into production-ready systems.
My goal is always to deliver solutions that are **simple, efficient, and genuinely useful for the people using them.**
prajwalfullstack
Hi Im a full stack developer, a vibe coded MVP to Market ready product, I'm here to help
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
- I refactor AI-generated prototypes into production-grade applications with proper error handling, testing, and clean architecture (SOLID, DDD, hexagonal architecture)
- I set up the infrastructure AI tools don't touch: AWS hosting, CI/CD pipelines, automated deployments, database optimization, monitoring, and alerting
- I integrate external services: payment providers, email systems, partner APIs, SSO/auth
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.
Prakash Prajapati
I’m a Senior Python Developer specializing in building secure, scalable, and highly available systems. I work primarily with Python, Django, FastAPI, Docker, PostgreSQL, and modern AI tooling such as PydanticAI, focusing on clean architecture, strong design principles, and reliable DevOps practices. I enjoy solving complex engineering problems and designing systems that are maintainable, resilient, and built to scale.
Yovel Cohen
I got a lot of experience in building Long-horizon AI Agents in production, Backend apps that scale to millions of users and frontend knowledge as well.
Dor Yaloz
SW engineer with 6+ years of experience,
I worked with React/Node/Python
did projects with React+Capacitor.js for ios
Supabase expert
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.
zipking
I am a technologist and product builder dedicated to creating high-impact solutions at the intersection of AI and specialized markets. Currently, I am focused on PropScan (EstateGuard), an AI-driven SaaS platform tailored for the Japanese real estate industry, and exploring the potential of Archify.
As an INFJ-T, I approach development with a "systems-thinking" mindset—balancing technical precision with a deep understanding of user needs. I particularly enjoy the challenge of architecting Vertical AI SaaS and optimizing Small Language Models (SLMs) to solve specific, real-world business problems. Whether I'm in a CTO-level leadership role or hands-on with the code, I thrive on building tools that turn complex data into actionable value.
You don't need to be technical. Just describe what's wrong and a verified developer will handle the rest.
Get HelpFrequently Asked Questions
What is the difference between validation and sanitization?
Validation checks that input meets your requirements (correct format, length, type) and rejects bad input. Sanitization modifies input to remove dangerous content while keeping the data. You should do both: validate first, then sanitize what passes.
Does React protect against XSS automatically?
React's JSX auto-escapes content in curly braces ({variable}), which prevents most XSS. However, using dangerouslySetInnerHTML, creating elements via DOM APIs, or setting href/src attributes with user data can still introduce XSS vulnerabilities.