Update product attribute value programmatically in Magento 2 .

<?php

namespace VendoreModuleHelper;

use MagentoCatalogModelProductAction as ProductAction;
use MagentoCatalogModelResourceModelProductCollectionFactory;
use MagentoFrameworkAppHelperAbstractHelper;
use MagentoFrameworkAppHelperContext;
use MagentoStoreModelStoreManagerInterface;

class Data extends AbstractHelper
{
    protected $messageManager;
    private $productCollection;
    private $productAction;
    private $storeManager;

    public function __construct(
        Context $context,
        CollectionFactory $collection,
        ProductAction $action,
        StoreManagerInterface $storeManager
    )
    {
        $this->productCollection = $collection;
        $this->productAction = $action;
        $this->storeManager = $storeManager;
        parent::__construct($context);
    }

    public function setcustomAttributeData($param)
    {
        try {
            $collection = $this->productCollection->create()->addFieldToFilter('*');
            $storeId = $this->storeManager->getStore()->getId();
            $ids = [];
            $i = 0;
            foreach ($collection as $item) {
                $ids[$i] = $item->getEntityId();
                $i++;
            }
            $this->productAction->updateAttributes($ids, array('attribute' => $param), $storeId);

        } catch (Exception $e) {
            $this->messageManager->addError($e->getMessage());
        }
    }
}