`annotation_layer.js` has logic to keep input elements in sync. The logic uses `document.getElementsByName` with [a name derived from the PDF](https://github.com/mozilla/pdf.js/blob/10a1db698047e612e8ae3da66d12a6c1ac5597a3/src/core/annotation.js#L407) to retrieve the set of related elements. This query is not namespaced, so if the viewer ever adds a `name` attribute to a checkbox or radio input in the page, then the PDF file can get it changed (without user interaction via the scripting interface). Fortunately, there doesn't appear to be any input/radio element in the default viewer code. A custom viewer can be affected by this bug, however.

I suggest to replace the `document.getElementsByTagName` calls with a function that checks that the elements are created by the `annotation_layer.js` code before returning them. There are several ways to do so, e.g. by adding a custom attribute to each input element.

## Seemingly generic property assignment
This code on its own looks dangerous because it allows the caller to overwrite any property
https://github.com/mozilla/pdf.js/blob/99e442941c16561e8826a925b164d79f4ad51fbf/src/display/annotation_layer.js#L684-L688
Fortunately, it is only called with a fixed key, so only the `value` property can be updated in response to user input events:
https://github.com/mozilla/pdf.js/blob/99e442941c16561e8826a925b164d79f4ad51fbf/src/display/annotation_layer.js#L732-L740

## Unchecking other checkboxes on checkbox state change
https://github.com/mozilla/pdf.js/blob/99e442941c16561e8826a925b164d79f4ad51fbf/src/display/annotation_layer.js#L979-L990

## Updating the abstract state (storage)
https://github.com/mozilla/pdf.js/blob/99e442941c16561e8826a925b164d79f4ad51fbf/src/display/annotation_layer.js#L1061-L1065

## Allowing scripts to uncheck checkbox/radio inputs
The others require user interaction to have any effect; this one allows scripts embedded in the PDF to run logic without user interaction.
https://github.com/mozilla/pdf.js/blob/99e442941c16561e8826a925b164d79f4ad51fbf/src/display/annotation_layer.js#L1073-L1077
(typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) && isNodeJS
    ? NodeCMapReaderFactory
    : DOMCMapReaderFactory;
const DefaultStandardFontDataFactory =
  (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) && isNodeJS
    ? NodeStandardFontDataFactory
    : DOMStandardFontDataFactory;
/**
 * @typedef {function} IPDFStreamFactory
 * @param {DocumentInitParameters} params - The document initialization
 *   parameters. The "url" key is always present.
 * @returns {Promise} A promise, which is resolved with an instance of
 *   {IPDFStream}.
 * @ignore
 */
/**
 * @type IPDFStreamFactory
 * @private
 */
let createPDFNetworkStream;
/**
 * Sets the function that instantiates an {IPDFStream} as an alternative PDF
 * data transport.
 *
 * @param {IPDFStreamFactory} pdfNetworkStreamFactory - The factory function
 *   that takes document initialization parameters (including a "url") and
 *   returns a promise which is resolved with an instance of {IPDFStream}.
 * @ignore
 */
function setPDFNetworkStreamFactory(pdfNetworkStreamFactory) {