A breached password is a password that has been exposed during a security incident, such as a data breach, where unauthorized individuals gain access to sensitive data. When a password is breached, it often becomes available to cybercriminals through underground forums, data dumps, or public leaks. Using a breached password significantly increases the risk of unauthorized access to accounts, as attackers may use automated tools to try these known credentials across multiple websites and services (a tactic called credential stuffing). To protect against this threat, users should avoid reusing passwords and regularly check if their credentials have been compromised using trusted services. Promptly changing any breached password is crucial to maintaining account security.