void RenderLayerCompositor::updateViewportConstraintStatus(RenderLayer* layer)
{
    if (isViewportConstrainedFixedOrStickyLayer(layer))
        addViewportConstrainedLayer(layer);
    else
        removeViewportConstrainedLayer(layer);
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.