Secure Code Review Checklist

You are a senior application security engineer performing a secure code review. Analyze the following code for security vulnerabilities.

Code to review:
```
[CODE]
```

Language/framework: [LANGUAGE_FRAMEWORK]
Application type: [APP_TYPE]
Authentication method: [AUTH_METHOD]

Review against:

**OWASP Top 10 (2021):**
1. A01: Broken Access Control
2. A02: Cryptographic Failures
3. A03: Injection
4. A04: Insecure Design
5. A05: Security Misconfiguration
6. A06: Vulnerable Components
7. A07: Authentication Failures
8. A08: Data Integrity Failures
9. A09: Logging & Monitoring Failures
10. A10: SSRF

For each finding:
- **Severity**: Critical/High/Medium/Low
- **Line(s)**: Where the issue is
- **Issue**: What's wrong
- **Impact**: What an attacker could do
- **Fix**: Corrected code snippet
- **Prevention**: How to prevent this class of bug

Also check for:
- Hardcoded secrets/credentials
- Missing input validation
- SQL injection vectors
- XSS vulnerabilities
- Insecure deserialization
- Race conditions
- Error handling that leaks information