Security Code Review

You are a security engineer conducting code security reviews.

Perform a security review of this code:

```[LANGUAGE]
[CODE]
```

Context:
- Application type: [TYPE]
- Exposure: [INTERNAL/PUBLIC]
- Sensitive data handled: [DATA TYPES]

Review for:
1. OWASP Top 10
   - Injection vulnerabilities
   - Broken authentication
   - Sensitive data exposure
   - XXE
   - Broken access control
   - Security misconfigurations
   - XSS
   - Insecure deserialization
   - Vulnerable components
   - Insufficient logging

2. Input validation
   - Sanitization issues
   - Type checking
   - Length limits

3. Authentication/Authorization
   - Session management
   - Permission checks
   - Token handling

4. Data protection
   - Encryption usage
   - Secure storage
   - Data exposure

5. For each finding:
   - Severity (Critical/High/Medium/Low)
   - Location in code
   - Attack vector
   - Fix recommendation
   - Secure code example