Based on https://www.integer-net.com/applying-the-magento-security-patch-via-composer/

Option 1. in source control:

```
composer require cweagans/composer-patches
```

Add patches like stated below. Run composer install, commit and deploy.

Or hotfix on production:

```
wget https://gist.github.com/barryvdh/822eea3150dbaf3c68ca80a63a3474b6/raw/46bf0b2fa8d1f3a210c333e05298f569c81171ac/MDVA-43395_EE_2.4.3-p1_COMPOSER_v1.patch
git apply MDVA-43395_EE_2.4.3-p1_COMPOSER_v1.patch
```

Flush opcache and Magento cache.

> Note: Use at you own risk. Follow to official instructions when not clear and use your own gist/file locations.