`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
this.id - 1,
        this.eventBus
      );
    this.structTreeLayerFactory = options.structTreeLayerFactory;
    this.renderer = options.renderer || RendererType.CANVAS;
    this.l10n = options.l10n || NullL10n;
    this.paintTask = null;
    this.paintedViewportMap = new WeakMap();
    this.renderingState = RenderingStates.INITIAL;
    this.resume = null;
    this._renderError = null;
    this._isStandalone = !this.renderingQueue?.hasViewer();
    this.annotationLayer = null;
    this.textLayer = null;
    this.zoomLayer = null;
    this.xfaLayer = null;
    this.structTreeLayer = null;
    const div = document.createElement("div");
    div.className = "page";
    div.style.width = Math.floor(this.viewport.width) + "px";
    div.style.height = Math.floor(this.viewport.height) + "px";
    div.setAttribute("data-page-number", this.id);
    div.setAttribute("role", "region");
    this.l10n.get("page_landmark", { page: this.id }).then(msg => {
      div.setAttribute("aria-label", msg);
    });
    this.div = div;
    container.appendChild(div);
  }
  setPdfPage(pdfPage) {