Here's why:
* Verb: The base form is "overreact" (to react excessively).
* Past Participle: "Overreacted" is used in these ways:
* Past Tense: "She overreacted to the news."
* Perfect Tenses: "He has overreacted in the past." "They had overreacted to the situation."
* Passive Voice: "The situation was overreacted to."
Let me know if you have any other words you'd like to analyze!