Ech0 before 4.7.3 Unauthenticated Like Endpoint Metric Inflation

Ech0 before 4.7.3 contains an authentication bypass vulnerability in the PUT /api/echo/like/:id endpoint that allows unauthenticated attackers to increment engagement metrics without identity verification or rate limiting. Attackers can send repeated requests to arbitrarily inflate the fav_count field for any known echo identifier, compromising the integrity of engagement metrics and social ranking systems.