Exposed Source Maps
Exposed source maps allow anyone to read your original source code — including API endpoints, business logic, and internal comments. SaaSalyst checks whether your JavaScript files have publicly accessible .map files, detecting a security risk that can reveal your entire codebase to attackers.
What SaaSalyst Checks
SaaSalyst identifies JavaScript files referenced in your HTML via <script src="..."> tags. For each JS file (up to 5), the scanner sends an HTTP HEAD request to the corresponding .map file (e.g., app.js → app.js.map). A 200 response indicates the source map is publicly accessible.
Why This Matters
Source maps are development tools that map minified production code back to original source files. They're essential for debugging but should never be publicly accessible in production.
An exposed source map lets attackers read your complete source code: API routes, authentication logic, business rules, API keys that might be embedded, and internal comments that reveal security assumptions.
This is a common misconfiguration — many build tools generate source maps by default and many deployment platforms serve them without explicit configuration to block access.
40%
Higher secret exposure in repos using AI coding assistants
GitGuardian 2025 Report
400+
Exposed secrets found across 5,600 vibe-coded apps
Escape.tech
How to Fix It
- Configure your build tool to either not generate source maps in production, or generate them but upload to a private error tracking service (like Sentry).
- For Next.js, set productionBrowserSourceMaps: false in next.config.js (this is the default).
- If you need source maps for debugging, use hidden source maps that upload to your error tracking tool but aren't referenced in the JS files.
- Verify the fix by checking if https://yourdomain.com/path/to/bundle.js.map returns a 404.
Frequently Asked Questions
How does SaaSalyst check for exposed source maps?
SaaSalyst finds JavaScript files in your HTML, then checks if corresponding .map files are publicly accessible by making HTTP requests. A 200 response means source maps are exposed.
Why are exposed source maps dangerous?
Source maps reveal your complete original source code — API routes, business logic, authentication code, and internal comments. SaaSalyst flags this because it gives attackers a roadmap to your application.
How do exposed source maps affect my Business Readiness Score?
SaaSalyst rates exposed source maps as medium severity in Security & Infrastructure. They represent a significant information disclosure risk that enterprise security teams flag during vendor assessments.
References & Official Sources
Official regulatory and standards sources relevant to the checks SaaSalyst runs on your site.
- OWASP Top 10— OWASP
- Security Headers Reference— Mozilla
- HSTS Preload List— Google
Check Your SaaS Now — Free
SaaSalyst scans your website in 30 seconds and checks for Exposed Source Maps along with 40+ other business readiness signals.
Scan Your App