`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
return this._transport.loadingParams;
  }
  /**
   * @type {PDFDocumentLoadingTask} The loadingTask for the current document.
   */
  get loadingTask() {
    return this._transport.loadingTask;
  }
  /**
   * @returns {Promise<Uint8Array>} A promise that is resolved with a
   *   {Uint8Array} containing the full data of the saved document.
   */
  saveDocument() {
    if (
      (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) &&
      this._transport.annotationStorage.size <= 0
    ) {
      deprecated(
        "saveDocument called while `annotationStorage` is empty, " +
          "please use the getData-method instead."
      );
    }
    return this._transport.saveDocument();
  }
  /**
   * @returns {Promise<Array<Object> | null>} A promise that is resolved with an
   *   {Array<Object>} containing /AcroForm field data for the JS sandbox,
   *   or `null` when no field data is present in the PDF file.
   */
  getFieldObjects() {