Explanation:

Box 1: A remediation request
Block a vulnerable app until the app is updated.
Block vulnerable applications
How to block vulnerable applications
* Go to Vulnerability management > Recommendations in the Microsoft 365 Defender portal.
* Select a security recommendation to see a flyout with more information.
* Select Request remediation.
* Select whether you want to apply the remediation and mitigation to all device groups or only a few.
* Select the remediation options on the Remediation request page. The remediation options are software update, software uninstall, and attention required.
* Pick a Remediation due date and select Next.
* Under Mitigation action, select Block or Warn. Once you submit a mitigation action, it is immediately applied.
* Review the selections you made and Submit request. On the final page you can choose to go directly to the remediation page to view the progress of remediation activities and see the list of blocked applications.
Box 2: A file indicator
Block an application executable based on a file hash.
While taking the remediation steps suggested by a security recommendation, security admins with the proper permissions can perform a mitigation action and block vulnerable versions of an application. File indicators of compromise (IOC)s are created for each of the executable files that belong to vulnerable versions of that application. Microsoft Defender Antivirus then enforces blocks on the devices that are in the specified scope.
The option to View details of blocked versions in the Indicator page brings you to the Settings > Endpoints > Indicators page where you can view the file hashes and response actions.
Reference:
https://learn.microsoft.com/en-us/microsoft-365/security/defender-vulnerability-management/tvm-block-vuln-ap