Cross-Site Scripting (XSS) in PDFs stems from vulnerabilities in rendering engines or malicious JavaScript, enabling data exfiltration, session hijacking, and account takeover. Common vectors include storing malicious PDFs on servers and exploiting weaknesses in browser-embedded viewers to execute scripts within the host context. Mitigations involve implementing strict Content Security Policies, robust input sanitization, and forcing file downloads to prevent direct browser rendering. For more details, visit PortSwigger Research . Stored xss using PDF a bug? | by cryptoshant