The security of SHAREit has been a matter of concern in the past, as the app has been found to have some security vulnerabilities. However, the developers of SHAREit have since addressed many of these issues through updates, and the app is generally considered safe to use.
When you transfer files using SHAREit, the files are encrypted during the transfer to protect them from being intercepted by third parties. This means that it is difficult for others to access your files or data during the transfer.
However, it is still important to be cautious when using SHAREit or any other file-sharing app. You should only share files with people you trust, and be mindful of the types of files you are sharing. Additionally, it is important to keep your device and SHAREit app up to date with the latest security updates to ensure that any known vulnerabilities are patched.