Sensitive information exposure occurs when protected data can be read by someone without authorization. The exposed material may be source code, API tokens, SSH keys, session cookies, configuration files, logs, or backup data. Even when the flaw does not allow full system control, reading one file can reveal secrets that unlock other services.
In cyber security, this matters because stolen data is often reusable. Attackers may use leaked credentials to access repositories, cloud accounts, CI/CD runners, or internal admin panels. Exposure can happen through path traversal, misconfigured access controls, overly verbose error messages, debug endpoints, or insecure file storage. Defenders reduce the risk by enforcing least privilege, segregating secrets from application data, encrypting sensitive files, and rotating credentials after any suspected disclosure. Monitoring for unusual file reads and unexpected secret use can help catch abuse early.