What is a significant risk of using the same password across multiple sites?

Using the same password across multiple sites greatly increases vulnerability to unauthorized access. When an individual employs a single password for several accounts, the security of all those accounts hinges on the strength and confidentiality of that one password. If a cybercriminal manages to obtain this password through various means, such as phishing, data breaches, or keystroke logging, they gain immediate access to all associated accounts. This scenario is particularly dangerous because it can lead to widespread unauthorized access, compromising sensitive information and personal data across multiple platforms.

In contrast to the other options, which may suggest convenience or simplification, the reality is that cross-site password reuse significantly undermines the security framework designed to protect individual accounts. Therefore, adopting unique and robust passwords for different accounts is crucial in establishing a strong defense against potential breaches and ensuring users' online safety.