Senior LevelReact JS & React 19
What are critical security vulnerabilities in React Server Actions and how do you secure them?
❓ Interview Prompt: Explain Server Actions security, public HTTP POST endpoint exposure, authentication checks, payload schema validation with Zod, and CSRF protection.
React Server Actions are exported server functions exposed as public HTTP POST endpoints:
Critical Security Vulnerabilities:
1
Treat Inputs as Untrusted: Anyone can issue an HTTP POST to a Server Action endpoint with arbitrary parameters!
2
Authentication & Authorization: Always verify user session authentication and permissions inside the action body.
3
Schema Validation: Validate argument types and payloads using Zod or Pydantic before touching database layers.
Code Implementation Example
jsx
// app/actions.js
'use server';
import { z } from 'zod';
const UpdateEmailSchema = z.object({ email: z.string().email() });
export async function updateEmailAction(rawInput) {
// 1. Authenticate user session
const session = await getSession();
if (!session) throw new Error('Unauthorized');
// 2. Validate input schema
const { email } = UpdateEmailSchema.parse(rawInput);
await db.users.update({ where: { id: session.userId }, data: { email } });
}💡Securing React 19 Server Actions with session authentication and Zod schema validation.
🎯 Interview Key Takeaway
Treat Server Actions as public HTTP POST endpoints: always authenticate user sessions and validate inputs with Zod.
#Server Actions#Security#Zod#React 19#Senior
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