Php injection problems

Php injection is used to write a processing program in php, which is the kind of http (which can be written in js but must be written in php in special cases, no input verification. Is there any danger of being attacked? will it be able to be intruded into like a database ?, Stick the code. in this case, it's too vague ., What are you afraid of without using a database ?? String conversion to php injection
I wrote a processing program in php, that is, the kind of http that thunder converts to common (which can be written in js, but must be written in php in special cases)
No database is used, and no input verification is performed.

Is there a risk of being attacked, and will it be able to be intruded into like a database?

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It's too vague to stick the code.
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What are you afraid of without using a database ?? Is string conversion crashed?