Fly.io Security Issues
The most common security gaps in Fly.io applications — and how to fix them before they become an incident.
Results in minutes. From $9.
4 Security Issues Documented
Common vulnerabilities found in Fly.io applications
High Severity Issues
Secrets synchronization across regions
highA common failure mode in Fly.io applications: secrets synchronization across regions. Left unchecked, this can lead to data exposure, unauthorized access, or service abuse.
Third-party API abuse (OpenAI quota drained, Stripe charges made), lateral access to connected services, and disclosure of internal systems.
Open the deployed app in a browser, view-source on the main bundle, grep for patterns like `sk-`, `sk_live_`, `eyJ`, `AKIA`, `AIza`. A single match is a confirmed exposure.
Move all secrets server-side (environment variables, serverless functions). Rotate any keys previously in frontend code. Audit bundles for leftover credentials before each deploy.
Medium Severity Issues
Edge deployment security
mediumA common failure mode in Fly.io applications: edge deployment security. Left unchecked, this can lead to data exposure, unauthorized access, or service abuse.
Account takeover of legitimate users. Attackers gain full access to victim accounts and any data/actions those accounts permit.
Attempt 20+ login requests with the same username in under 60 seconds. If all complete without rate limiting or lockout, the issue is present.
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.
Private networking configuration
mediumA common failure mode in Fly.io applications: private networking configuration. Left unchecked, this can lead to data exposure, unauthorized access, or service abuse.
Account takeover of legitimate users. Attackers gain full access to victim accounts and any data/actions those accounts permit.
Attempt 20+ login requests with the same username in under 60 seconds. If all complete without rate limiting or lockout, the issue is present.
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.
Volume and persistence security
mediumA common failure mode in Fly.io applications: volume and persistence security. Left unchecked, this can lead to data exposure, unauthorized access, or service abuse.
Account takeover of legitimate users. Attackers gain full access to victim accounts and any data/actions those accounts permit.
Attempt 20+ login requests with the same username in under 60 seconds. If all complete without rate limiting or lockout, the issue is present.
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.
How to Prevent These Issues
- Run automated security scans before every deployment
- Configure database access controls (RLS/Security Rules) first
- Store all secrets in environment variables, never in code
- Enable email verification and strong password policies
- Add security headers to your hosting configuration
- Review AI-generated code for security before accepting
Find Issues Before Attackers Do
VAS scans your Fly.io app for all these issues automatically. Scans from $9, instant results.
Get Starter ScanFrequently Asked Questions
What are the most common Fly.io security issues?
The most common issues are: exposed API keys/secrets, missing database access controls (RLS or Security Rules), weak authentication configuration, and missing security headers. These account for over 80% of vulnerabilities in Fly.io applications.
How do I find security issues in my Fly.io app?
Run a VAS security scan for automated detection of common vulnerabilities. Manually check: database access controls, search code for hardcoded secrets, verify authentication settings, and test security headers. VAS catches all of these automatically.
Are Fly.io security issues fixable?
Yes, nearly all Fly.io security issues are configuration problems with straightforward fixes. Missing RLS, exposed secrets, weak auth—all have clear remediation steps. Most fixes take under an hour to implement.
How quickly can Fly.io security issues be exploited?
Exposed databases and API keys can be discovered within minutes using automated scanners. Attackers actively scan for common patterns. This is why security configuration must happen before deployment, not after.
Does Fly.io have built-in security?
Fly.io provides security features, but they require configuration. Security isn't automatic—you must enable database access controls, manage secrets properly, configure auth settings, and add security headers. The tools exist; you must use them.
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Last updated: April 20, 2026