Next.js Security Scanner
Building with Next.js? The framework is solid. The findings come from the server and client boundary.
Enter your deployed app's URL. Review the findings, take the suggested fixes to your coding tool, and retest after making changes.
First scan free: issue counts and one finding revealed in detail. No card required.
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 check the reachable app for exposed secrets, browser protections, authentication issues and database access problems. A standard scan typically takes a few minutes; blocked requests or incomplete coverage are reported.
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 does a VAS scan of a Next.js app check?
VAS checks the deployed pages, scripts and endpoints it can reach for issues including env exposure, route handlers, server actions, headers. The report records findings and coverage limits; it does not certify the whole app as secure.
What will I receive in the report?
Findings include severity, supporting evidence and remediation guidance. Your first scan is free, with issue counts and one finding revealed in detail. Paid report access unlocks every finding. Use Export for AI to bring available findings into your coding tool, review the proposed changes and retest.
Can a scan verify every permission and private workflow?
No. Coverage depends on reachable pages, discovered endpoints and enabled checks. Configure a test login for supported authenticated checks. Review source code and business-specific permissions separately. Zero findings does not prove an app is secure.
Does VAS change my code or database policies?
VAS provides recommendations, not automatic fixes. Adapt any suggested policy or code change to your data model, test that permitted users still have access and that other users do not, then rescan. Read checks alone cannot confirm insert, update or delete permissions.
What should I know before scanning a production app?
Only scan apps you own or have permission to test. Scan requests can trigger firewall rules, logs and rate limits. Review enabled checks, and use staging or dedicated test accounts for sensitive workflows. Active tests, where enabled, need separate care because they can make changes.
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
Rescan after deploying a fix to check whether the original finding still appears. Compare the evidence and coverage with the previous report. For permissions and private workflows, also repeat the relevant tests with authorized and unauthorized test users.
Check your Next.js app
Find observable security issues in your deployed app, review the evidence and take the next steps with your coding tool.
Start with a free scan. See issue counts and one finding in detail, then decide whether you need full report access.
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.