Sensitive does not mean it is not readable. It is just simply not exposed through the UI. It can be easily leaked if you return a bit too much props from the action functions or routes.
The only way to defend against these types of issues is to encrypt your environment with your own keys, with secrets possibly baked into source as there are no other facilities to separate them. An attacker would need to not only read the environments but also download the compiled functions and find the decryption keys.
It is not ideal but it could work as a workaround.
The better way to defend against these types of issues is to avoid Vercel and similar providers
> with secrets possibly baked into source
please don't suggest this. The right way is to have the creds fetched from a vault, which is programmed to release the creds auth-free to your VM (with machine level identify managed by the parent platform)
This is how Google Secrets or AWS Vaults work.