`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
const currentScale = this._currentScale;
    const currentScaleValue = this._currentScaleValue;
    const normalizedScaleValue =
      parseFloat(currentScaleValue) === currentScale
        ? Math.round(currentScale * 10000) / 100
        : currentScaleValue;
    const pageNumber = firstPage.id;
    let pdfOpenParams = "#page=" + pageNumber;
    pdfOpenParams += "&zoom=" + normalizedScaleValue;
    const currentPageView = this._pages[pageNumber - 1];
    const container = this.container;
    const topLeft = currentPageView.getPagePoint(
      container.scrollLeft - firstPage.x,
      container.scrollTop - firstPage.y
    );
    const intLeft = Math.round(topLeft[0]);
    const intTop = Math.round(topLeft[1]);
    pdfOpenParams += "," + intLeft + "," + intTop;
    this._location = {
      pageNumber,
      scale: normalizedScaleValue,
      top: intTop,
      left: intLeft,
      rotation: this._pagesRotation,
      pdfOpenParams,
    };
  }
  _updateHelper(visiblePages) {