API Route Missing Authentication
API routes that handle user data without checking authentication. Anyone with the URL can call them — no login required.
What this rule detects
VC003 flags route handlers (Next.js App Router routes and server actions, Express and Hono routes, Vercel and Netlify functions, Supabase Edge Functions) whose handler contains no recognized auth check (`await auth()`, `getServerSession()`, `requireUser()`, `currentUser()`, `supabase.auth`, `jwt.verify`, a 401 response, etc.). It does not look at what the handler does, so an endpoint that is public by design needs a `// VC003-OK: <reason>` comment.
Vulnerable vs. safe code
// Anyone who finds this URL can read every user.
export async function GET() {
const users = await db.user.findMany();
return Response.json(users);
}import { auth } from "@clerk/nextjs/server";
export async function GET() {
const { userId } = await auth();
if (!userId) {
return Response.json({ error: "Unauthorized" }, { status: 401 });
}
// Only return data the requesting user is allowed to see.
const users = await db.user.findMany({
where: { orgId: await getOrgId(userId) },
});
return Response.json(users);
}Authentication ("who are you?") and authorization ("are you allowed to do this?") are different. VC003 catches missing authentication. VC158 (paid plans) flags routes that fetch a record by an ID from the URL without checking the requesting user owns it.
About A01:2021 — Broken Access Control
Access-control bugs let users do things they shouldn't — view another user's data, modify records they don't own, or hit admin-only endpoints without admin rights. This class moved to #1 in the 2021 OWASP Top 10; OWASP reports that 94% of applications were tested for some form of broken access control, with an average incidence rate of 3.81%.
Impact: An attacker who finds an access-control bug typically gets a much bigger blast radius than other vulnerability classes. Examples we've seen in AI-generated code: a /api/user/[id] route that returns any user's profile, a delete endpoint that doesn't check ownership, an admin dashboard with no role check.
How to fix it: Check authentication AND authorization on every server-side route. Never rely on the client to enforce permissions. Default to deny. For per-resource checks, fetch the resource and verify the requesting user owns it before returning or modifying it.
Common patterns in this category:
- Missing auth check on API routes (the resource is returned to anyone with the URL)
- Authorization based on a parameter the client controls (e.g. trusting `?userId=` in the URL)
- Direct object references where the resource ID isn't validated against the requesting user
- Public access to administrative or internal endpoints
- Privilege escalation via mass assignment (user POSTs `{role: 'admin'}` and the ORM accepts it)
- State-changing routes without CSRF protection
Framework mapping
Findings from this rule map to the following framework controls. This is an informational mapping, not an audit, certification, or attestation.
See the full compliance coverage page for how every rule maps to OWASP Top 10 and CWE, and which rules also carry informational SOC 2 and ISO 27001 cross-references.
Scan your code for VC003
Free, no signup: paste code or upload a file, or run npx xploitscan@latest scan . The free scan runs 30 core rules; paid plans run all 223.