Code Reviewer For You

I have reviewed the getUser function. The code contains a critical security vulnerability and lacks basic error handling for empty results.

Findings

[Critical] SQL Injection Vulnerability

Location: getUser function, query string construction.
Issue: The function uses string concatenation to build a SQL query with untrusted input id.
Why it matters: An attacker could pass a malicious string (e.g., 1 OR 1=1) to bypass authentication or extract the entire user database.
Recommended fix: Use parameterized queries or a prepared statement provided by your database driver.

const getUser = async (id) => {
  const query = "SELECT * FROM users WHERE id = ?";
  const user = await db.execute(query, [id]);
  return user[0] || null;
};

[Medium] Unhandled Empty Result

Location: return user[0];
Issue: If the database returns an empty array, accessing user[0] returns undefined.
Why it matters: Calling code might expect a null value or an object, and subsequent property access on undefined will throw a runtime error.
Recommended fix: Explicitly handle the empty case by returning null or throwing a specific 404 error.

What Looks Good

• The function correctly uses async/await for non-blocking I/O.
• The naming convention is clear and follows standard JavaScript practices.

Suggested Tests

• Injection Test: Call getUser("' OR 1=1 --") and verify the query fails or returns nothing.
• Empty Result Test: Call getUser with a non-existent ID and ensure it returns null without crashing.

Final Verdict

• Overall risk: Critical
• Priority fixes: Implement parameterized queries immediately.
• Confidence: High

Next steps

1. Update the database driver calls to use prepared statements.
2. Add a guard clause for the return value.
3. Verify if similar concatenation patterns exist elsewhere in the data layer.