Vibe codingHardvc-g114

Subject Ai code reviewLevel Senior–Staff~20 minCommon in Security interviewsIndustries Software development

Question

An AI built this comment renderer so users can post markdown-ish HTML. It passed code review and shipped. Identify the vulnerability and what an attacker can do.

tsx

1function Comment({ body }: { body: string }) {2  const html = body.replace(/\n/g, '<br/>');3  return (4    <div5      className="comment"6      dangerouslySetInnerHTML={{ __html: html }}7    />8  );9}

What a strong answer looks like

Treat the AI’s output as a draft to verify, not an answer to trust. Name the specific flaw and the input that triggers it, say how you’d catch it — tests, edge cases, reading critically — and how you’d re-prompt or decompose to get it right.

Learn the concepts

Describe your solution

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.