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Expert track

Prototype Pollution

Merging __proto__ poisons every object. Guard the keys.

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Final exam

3 questions in 10 minutes, 3 to pass. Certificates require it.

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  1. 01How prototype pollution worksRecursive merge plus a magic key equals global contamination.
  2. 02Lab: poison the prototypeAn unguarded merge meets a magic key. Watch every object change.
  3. 03Prototype pollution quizThree questions on the mechanism, impact, and guards.