Security Code Audit

Perform a security review of the following code.

Code to Review:
```
[paste your code]
```

Security Context:
- Application type: [web / API / CLI / mobile]
- Data sensitivity: [PII / financial / public / internal]
- Authentication: [how users are authenticated]
- Deployment: [cloud / on-prem / edge]

Security Review Request:
1. Vulnerability Scan — Check for Injection, XSS, CSRF, Authentication flaws, Authorization flaws, Sensitive data exposure, Security misconfiguration, Insecure dependencies.
2. Detailed Findings — For each vulnerability found provide Issue, Risk level, Proof of concept, Fix, Prevention.
3. Secure Code Version — Secured version with security comments.
4. Security Checklist — Input validation, Output encoding, Authentication, Authorization, Data protection, Error handling, Logging.
5. Recommendations — Prioritized security improvements.