Next.js Security Scanner
Building with Next.js? The framework is solid. The findings come from the server and client boundary.
Our automated security scanner analyzes your Next.js application for vulnerabilities, misconfigurations, and exposed secrets. Get a comprehensive security report in minutes, not days.
Next.js Security Considerations
Next.js makes development fast, but AI-generated code often skips security best practices:
- !NEXT_PUBLIC_ variables baked into the client bundle
- !Route handlers without authentication or ownership checks
- !Middleware treated as a security perimeter it cannot be
- !Server actions callable without re-verifying the caller
Where Security Breaks in Next.js Apps
Built on Supabase (Postgres + RLS), Next.js applications share a recognizable fingerprint, which means attackers and automated scanners find them the same way every time. Based on real vulnerability patterns in Next.js deployments, the breakdown is 0 critical-impact issues, 1 high-impact, and 3 medium-or-lower.
NEXT_PUBLIC_ variables baked into the client bundle
A common failure mode in Next.js applications: next_public_ variables baked into the client bundle. Left unchecked, this can lead to data exposure, unauthorized access, or service abuse.
Fix: Scan your deployed application with a security tool that understands this stack. Address the specific findings — generic best practices don't catch platform-specific misconfigurations.
Route handlers without authentication or ownership checks
A common failure mode in Next.js applications: route handlers without authentication or ownership checks. Left unchecked, this can lead to data exposure, unauthorized access, or service abuse.
Fix: Enforce email verification, minimum password requirements, and rate limiting on auth endpoints. Test auth flows as unauthenticated and cross-user to verify access controls.
Middleware treated as a security perimeter it cannot be
A common failure mode in Next.js applications: middleware treated as a security perimeter it cannot be. Left unchecked, this can lead to data exposure, unauthorized access, or service abuse.
Fix: Scan your deployed application with a security tool that understands this stack. Address the specific findings — generic best practices don't catch platform-specific misconfigurations.
Server actions callable without re
verifying the caller
Fix: Scan your deployed application with a security tool that understands this stack. Address the specific findings — generic best practices don't catch platform-specific misconfigurations.
What We Check
Env Exposure
Find secrets in the client bundle.
Route Handlers
Test API routes for missing auth.
Server Actions
Check actions re-verify the caller.
Headers
Verify security headers are configured.
What You'll Get
Why Next.js Apps Need Security Scanning
Next.js apps had the lowest critical rate of any stack we scan in volume. The framework defaults are sensible, and the issues that remain are almost all about what you put on which side of the server boundary.
vas checks the deployed result: what actually shipped in the bundle, and which routes answer without a session.
How Next.js Security Scanning Works
Submit Your URL
Enter your Next.js application URL. Our scanner automatically detects your tech stack and configures the appropriate security checks for Next.js.
Automated Analysis
We scan for exposed secrets, security headers, authentication issues, database misconfigurations, and Next.js-specific vulnerabilities. A deep scan typically completes in 20-30 minutes.
Get Actionable Results
Receive a detailed report with prioritized vulnerabilities, severity ratings, and step-by-step remediation guidance with code examples specific to Next.js.
Common Questions About Next.js Security
What vulnerabilities are most common in Next.js apps?
The top finding classes in Next.js apps: next_public_ variables baked into the client bundle; route handlers without authentication or ownership checks; middleware treated as a security perimeter it cannot be.
What does a vas scan of a Next.js app check?
The scan probes your deployed app for the specific findings above: env exposure, route handlers, server actions, headers. It actually attempts each vulnerability class (not just header inspection) and reports results with severity + fix for each.
Is running a scan safe for production?
Yes. The scanner uses read-only probes against public endpoints: no data modification, no destructive tests. A deep scan typically finishes in 20-30 minutes and will not impact application availability.
Remediation Playbook for Next.js
Priority-ordered fixes for the specific findings we see in Next.js apps. Critical items close data-exposure gaps; high items prevent compromise; medium items reduce attack surface. Applies to apps using Supabase (Postgres + RLS), the dominant Next.js stack.
1. NEXT_PUBLIC_ variables baked into the client bundle
Why it matters: A common failure mode in Next.js applications: next_public_ variables baked into the client bundle. Left unchecked, this can lead to data exposure, unauthorized access, or service abuse.
How to close it: Scan your deployed application with a security tool that understands this stack. Address the specific findings — generic best practices don't catch platform-specific misconfigurations.
2. Route handlers without authentication or ownership checks
Why it matters: A common failure mode in Next.js applications: route handlers without authentication or ownership checks. Left unchecked, this can lead to data exposure, unauthorized access, or service abuse.
How to close it: Enforce email verification, minimum password requirements, and rate limiting on auth endpoints. Test auth flows as unauthenticated and cross-user to verify access controls.
3. Middleware treated as a security perimeter it cannot be
Why it matters: A common failure mode in Next.js applications: middleware treated as a security perimeter it cannot be. Left unchecked, this can lead to data exposure, unauthorized access, or service abuse.
How to close it: Scan your deployed application with a security tool that understands this stack. Address the specific findings — generic best practices don't catch platform-specific misconfigurations.
4. Server actions callable without re
Why it matters: verifying the caller
How to close it: Scan your deployed application with a security tool that understands this stack. Address the specific findings — generic best practices don't catch platform-specific misconfigurations.
Verify the fixes stuck
Run a vas scan after applying each fix to confirm the gap is actually closed. "I applied the fix" is not evidence. The fix may have been partial, reverted, or not deployed. Re-scanning gives you proof, and a record for compliance if you ever need it.
Secure Your Next.js App
Don't let vulnerabilities compromise your hard work. Security issues in Next.js applications can lead to data breaches, unauthorized access, and damaged user trust. The average data breach costs startups between $120,000 and $1.24 million.
Run your first scan free, in minutes. Scan before you launch and deploy with confidence knowing your application meets security best practices.
More on Next.js Security
Every angle of Next.js security, from the specific findings we detect to step-by-step fixes.
Next.js Security Risks
Specific risks we find in Next.js apps, with real-world examples.
Next.js Security Issues
Issues grouped by severity with detection and fix steps.
Next.js Best Practices
Remediation playbook derived from Next.js's actual failure modes.
Is Next.js Safe?
Honest assessment of Next.js's production readiness.
Next.js Security Checklist
Pre-launch checklist covering every finding class for Next.js.
How to Secure Next.js Apps
Step-by-step hardening guide for Next.js deployments.