PDF/UA (PDF/Universal Accessibility) is the accessibility standard for PDF files. It requires proper tagging, logical reading order, headings, tables, alternative text, and other structural metadata so screen readers and similar assistive tools can interpret the document reliably. A PDF can look correct to a sighted user and still fail PDF/UA if it is just a scanned image or has broken tags.
In cyber security, PDF/UA matters because document workflows often mix accessibility, usability, and trust. Public portals, banks, and enterprises use it to validate that generated forms and notices are machine-readable and less likely to force unsafe workarounds or manual reformatting. Attackers also abuse PDFs in phishing and malware delivery; PDF/UA does not stop malicious code, but standards-checked documents are easier to inspect, archive, and process safely.