Security Vulnerability Audit

Conduct a security audit on the following ⟨LANGUAGE⟩ code, focusing on common vulnerabilities for [CONTEXT, e.g., web applications, APIs, data processing scripts].

```⟨LANGUAGE⟩
[PASTE CODE BLOCK]
```

Check specifically for:
- Injection flaws (SQL, NoSQL, OS command, LDAP)
- Cross-Site Scripting (XSS) and Cross-Site Request Forgery (CSRF)
- Insecure direct object references (IDOR)
- Sensitive data exposure (secrets in code, PII in logs)
- Improper authentication/authorization logic
- Use of deprecated or insecure libraries/functions
- Missing input validation or output encoding

For each vulnerability found:
- Severity: Critical / High / Medium / Low
- Description of the attack vector
- Secure code fix with explanation