PDF leakage is the exposure of Portable Document Format files that contain sensitive information such as invoices, employee records, contracts, tax data, or identity numbers. Because PDFs are easy to copy, open, and share, they are a common format for stolen documents to appear in extortion campaigns and public leak sites.
In cyber security, PDF leakage matters because document files can reveal more than a database dump: they may expose personal identifiers, internal business processes, signatures, or confidential attachments. Attackers often exfiltrate large PDF collections during a breach and use them as pressure for ransom or coercion. Defenders reduce the risk by controlling document access, encrypting sensitive files, monitoring unusual exports or archive creation, and applying data loss prevention to detect large outbound document transfers.