Why does frontend care about prototype pollution from JSON?
PICTURE THIS: GIT FLOW
Simple meaning
If we merge untrusted objects into a config with a recursive assign, an attacker can set __proto__ fields and change Object.prototype.
WHY — Security instead of guessing?
Why interviewers care about Security:
on Security.
the situation, the default choice, and one exception - that reads as experience.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1If we merge untrusted
objects into a config with a recursive assign, an attacker can set __proto__ fields and change Object.prototype.
- 2That can flip flags
like isAdmin in naive checks.
- 3I use Object.create null,
Map, or libraries that block proto keys.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
If we merge untrusted objects into a config with a recursive assign, an attacker can set __proto__ fields and change Object.prototype. That can flip flags like isAdmin in naive checks.