I'm doing a peer review and I have a question, if in the contract users can push as many object to an array mapped to their address how big a concern it is? Because on a low fee chain, I can check where my array start and if there are other data saved in the next reasonable amount of memory slot I could override them continuing pushing new objects
the object is like 5 slot, and I can create a ton of contract to see where their start of the array start and after I get a decent one I can create millions of push, for sure you can't spam crazy and fill the entire memory, but still if you land in a decent spot could be risky
what you think? Could be a security concern or not?

Even if the gas price is acceptable on L2 you could hit the gas block limit If the array is too big to loop

you didn't understand what I mean. I have a contract that have a deposit function, and at each deposit it make userInfo[msg.sender].push(
UserInfo(val1, val2, val3, val4, val5)
);

I can call this function as many time I want.

My concern is that if I create an attacking contract that for example call deposit 100_000 times staying inside block gas limit, I can public a ton of this contract until I get one where the start of the array in the mapping is before a important variable. In that case at each transaction i do with the attacking contract (that do a batch of 100k deposit) I can ovverride the next 500k slot in the storage, so doing some of this batch deposit I could ideally reach a variable like admin and ovverride it with whatever I want. My question is, in a l2 chain like polygon where you can do a ton of transaction, would this be a concern or based on the amount of slots is still not feasable?

Feels like you don't appreciate how big of a number 2^256 is :)

you right, did some actual calculation, and cosidering polygon throught put in 1 day you can consume 25M slots, and even if you can precompute the addresses of a deployed contract and them compute the possible landing position in the slot, the possibility to find it in 1 day using all bitcoing hash power is 1 in 10^56 XD