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Vibe codingHardvc-g494
Subject Ai code reviewLevel Mid–Senior~18 minCommon in Security interviewsIndustries Software development

Question

An AI built this FastAPI signup flow. The Pydantic model 'validates' the request, so the team assumed input was safe. A user signed themselves up as an admin with a free plan. Trace how, and fix the model.

python
class UserCreate(BaseModel):    email: str    password: str    role: str = "user"    plan: str = "free"    is_active: bool = True @app.post("/users")async def create_user(payload: UserCreate):    user = User(**payload.dict())    db.add(user); await db.commit()    return {"id": user.id}
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.