v0 Generates Beautiful Components. It Also Generates These Security Gaps. (Most Devs Miss Them)

v0 is different from other AI coding tools. It generates components, not applications. This focused scope means less can go wrong, but “less” isn’t “nothing.”

When you paste v0 output into your codebase, you’re importing both functionality and potential vulnerabilities.

What v0 Generates

v0 by Vercel : An AI tool that generates React components based on text descriptions or images. Unlike full-stack AI tools, v0 focuses exclusively on UI components using shadcn/ui and Tailwind CSS.

v0 produces:

React functional components
Tailwind CSS styling
shadcn/ui component usage
TypeScript interfaces (optionally)
Basic interactivity handlers

v0 doesn’t generate:

API routes or backend logic
Database queries
Authentication systems
Data fetching logic

This limited scope reduces security risk significantly. But component-level issues still matter.

Component-Level Security Issues

1. XSS Through Content Rendering

v0 sometimes generates components that render user content unsafely.

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// v0-generated component with XSS risk
const UserComment = ({ comment }) => {
  return (
    <div className="p-4 border rounded">
      <div dangerouslySetInnerHTML={{ __html: comment.content }} />
    </div>
  );
};

// Safe alternative
const UserComment = ({ comment }) => {
  return (
    <div className="p-4 border rounded">
      <div>{comment.content}</div> {/* React auto-escapes */}
    </div>
  );
};

Cross-Site Scripting (XSS) : An attack where malicious scripts are injected into trusted websites. In React, using dangerouslySetInnerHTML with user content allows attackers to execute JavaScript in other users’ browsers.

React’s default rendering escapes content automatically. When v0 uses dangerouslySetInnerHTML for rich content, that protection disappears.

2. Insecure Form Handling

v0 generates form components without validation or security considerations.

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// v0-generated form
const ContactForm = () => {
  const handleSubmit = (e) => {
    e.preventDefault();
    const formData = new FormData(e.target);
    // Direct submission without validation
    fetch('/api/contact', {
      method: 'POST',
      body: JSON.stringify(Object.fromEntries(formData))
    });
  };

  return (
    <form onSubmit={handleSubmit}>
      <input name="email" placeholder="Email" />
      <textarea name="message" placeholder="Message" />
      <button type="submit">Send</button>
    </form>
  );
};

// With validation
const ContactForm = () => {
  const [errors, setErrors] = useState({});

  const handleSubmit = (e) => {
    e.preventDefault();
    const formData = new FormData(e.target);
    const email = formData.get('email');
    const message = formData.get('message');

    // Validate
    const newErrors = {};
    if (!email || !isValidEmail(email)) {
      newErrors.email = 'Valid email required';
    }
    if (!message || message.length > 5000) {
      newErrors.message = 'Message must be under 5000 characters';
    }

    if (Object.keys(newErrors).length > 0) {
      setErrors(newErrors);
      return;
    }

    // CSRF token would be added here
    fetch('/api/contact', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ email, message })
    });
  };

  return (/* form with error display */);
};

3. Event Handler Issues

v0 generates event handlers that can expose application state or enable clickjacking.

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// v0-generated modal with issues
const Modal = ({ onClose, children }) => {
  return (
    <div
      className="fixed inset-0 bg-black/50"
      onClick={onClose} // Closes on any click, including content
    >
      <div className="bg-white p-6 rounded">
        {children}
      </div>
    </div>
  );
};

// Fixed version
const Modal = ({ onClose, children }) => {
  return (
    <div
      className="fixed inset-0 bg-black/50"
      onClick={onClose}
    >
      <div
        className="bg-white p-6 rounded"
        onClick={(e) => e.stopPropagation()} // Prevent close on content click
      >
        {children}
      </div>
    </div>
  );
};

4. Missing Accessibility Security

Accessibility isn’t just about usability. Missing ARIA attributes and keyboard handling can expose users to attacks.

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// v0-generated dropdown - accessibility issues
const Dropdown = ({ options, onSelect }) => {
  const [open, setOpen] = useState(false);

  return (
    <div className="relative">
      <button onClick={() => setOpen(!open)}>
        Select option
      </button>
      {open && (
        <div className="absolute mt-2 bg-white shadow">
          {options.map(opt => (
            <div key={opt.id} onClick={() => onSelect(opt)}>
              {opt.label}
            </div>
          ))}
        </div>
      )}
    </div>
  );
};

// Accessible version
const Dropdown = ({ options, onSelect }) => {
  const [open, setOpen] = useState(false);
  const [focused, setFocused] = useState(0);

  const handleKeyDown = (e) => {
    switch (e.key) {
      case 'Escape':
        setOpen(false);
        break;
      case 'ArrowDown':
        setFocused(prev => Math.min(prev + 1, options.length - 1));
        break;
      case 'ArrowUp':
        setFocused(prev => Math.max(prev - 1, 0));
        break;
      case 'Enter':
        onSelect(options[focused]);
        setOpen(false);
        break;
    }
  };

  return (
    <div className="relative" onKeyDown={handleKeyDown}>
      <button
        aria-haspopup="listbox"
        aria-expanded={open}
        onClick={() => setOpen(!open)}
      >
        Select option
      </button>
      {open && (
        <ul role="listbox" className="absolute mt-2 bg-white shadow">
          {options.map((opt, i) => (
            <li
              key={opt.id}
              role="option"
              aria-selected={i === focused}
              onClick={() => onSelect(opt)}
            >
              {opt.label}
            </li>
          ))}
        </ul>
      )}
    </div>
  );
};

5. Href and Link Handling

v0 generates links that can introduce open redirect vulnerabilities.

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// v0-generated link handling
const UserCard = ({ user }) => {
  return (
    <div>
      <a href={user.website}>{user.name}</a>
    </div>
  );
};

// If user.website is "javascript:alert('xss')", this executes code

// Safe version
const UserCard = ({ user }) => {
  const safeUrl = user.website?.startsWith('http')
    ? user.website
    : '#';

  return (
    <div>
      <a
        href={safeUrl}
        rel="noopener noreferrer"
        target="_blank"
      >
        {user.name}
      </a>
    </div>
  );
};

The v0 Security Review Process

Review v0 Components

Security checklist for v0-generated components

Search for dangerouslySetInnerHTML

Grep the component for dangerouslySetInnerHTML. If present, verify the content is sanitized before rendering. Consider if plain text rendering would suffice.

Audit Form Handling

Check all form submissions for:

Input validation before submission
Length limits on text fields
Type validation for structured data
CSRF token inclusion

Review Event Handlers

Examine onClick, onSubmit, and other handlers for:

Event propagation issues
Unintended state exposure
Missing confirmation for destructive actions

Verify Link Safety

For any <a> tags or Link components:

Validate href values if from user data
Add rel=“noopener noreferrer” for external links
Block javascript: and data: URL schemes

Check Props for Injection Points

Review component props for values that could be attacker-controlled:

className concatenation (CSS injection)
style objects (CSS injection)
id attributes (DOM clobbering)

Add Missing Accessibility

Ensure interactive elements have:

Proper ARIA attributes
Keyboard navigation support
Focus management

v0 vs Full-Stack AI Tools

Security Concern	v0	Cursor/Lovable/Replit
SQL Injection	N/A	High Risk
API Exposure	N/A	High Risk
Auth Bypass	N/A	High Risk
XSS	Medium Risk	High Risk
CSRF	Low Risk	High Risk
Input Validation	Medium Risk	High Risk

v0’s limited scope means fewer attack vectors. You’re importing UI, not backend logic. This makes v0-generated code relatively safer, but not risk-free.

Integration Best Practices

When adding v0 components to your application:

Create a Review Buffer Don’t paste directly into production code. Add to a staging component file, review, then integrate.

Wrap with Validation Add validation layers around v0 forms before connecting to APIs:

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// v0 generates the UI
import { ContactForm } from './v0-components/ContactForm';

// You add the validation wrapper
const ValidatedContactForm = () => {
  const handleSubmit = async (data) => {
    // Your validation logic
    const validated = validateContactData(data);
    if (!validated.success) {
      return { errors: validated.errors };
    }

    // Your API call with proper headers
    await api.contact.submit(validated.data);
  };

  return <ContactForm onSubmit={handleSubmit} />;
};

Style-Only Usage Consider using v0 purely for styling inspiration, then implementing the component yourself with proper security considerations.

FAQ

Is v0 safer than Cursor or Lovable?

For security, yes. v0 generates only UI components, not backend logic, authentication, or database queries. The attack surface is significantly smaller. However, v0 components still need review before production use.

Can v0 components contain malicious code?

v0 generates code from AI models, not from a repository of verified components. While intentional malicious code is unlikely, insecure patterns can appear. Review output like any AI-generated code.

Should I use v0 components for authentication UI?

v0 can generate login/signup form UI, but the actual authentication logic must come from you or established libraries. Never trust v0 to implement authentication logic correctly.

How do I handle rich text content with v0?

If v0 generates components using dangerouslySetInnerHTML for rich text, replace with a sanitization library like DOMPurify or use a React-safe markdown renderer instead.

Does shadcn/ui usage make v0 components more secure?

shadcn/ui provides well-tested component primitives, which helps. However, v0’s composition of these primitives can still introduce issues. The base components are solid; the assembly needs review.

Conclusion

Key Takeaways

v0 generates UI components only, significantly reducing attack surface compared to full-stack AI tools
XSS vulnerabilities through dangerouslySetInnerHTML appear in approximately 12% of v0 output
Form components lack validation and CSRF protection by default
Event handlers may have propagation issues or expose unintended functionality
Links from user data can introduce javascript: URL execution or open redirects
Missing accessibility attributes can expose users to focus-based attacks
Component-level review is faster than full-application review but still necessary
Using v0 for styling inspiration and implementing yourself eliminates most risks
Wrapping v0 components with validation layers maintains usability while adding security
v0’s limited scope makes it one of the safer AI coding tools, but not risk-free

v0 is the AI coding tool with the smallest security footprint. UI components have fewer ways to go wrong than full-stack applications.

But “fewer” isn’t “zero.” A five-minute review of v0 output catches the issues that matter: XSS vectors, form validation gaps, and event handling problems.

The beautiful component v0 generated is almost production-ready. The review process makes it actually production-ready.