A late payment is usually reported to the credit bureau when an entire building cycle is missed. This means that if you forget to pay your credit card bill on the day that it was due and remember the next day or a couple of days later it will probably not be reported to the credit bureaus. A late payment will probably only find its way on your credit history if it has still not been paid till the time that the next building cycle arrives. This is usually the case because lenders understand that mistakes can happen and anyone can forget to pay a bill on the due date.
However, if the late payment does find its way on your credit report it will have a negative impact on your credit score. It is possible that your credit score may use to for the first couple of months. This is because it will not be clear to the credit scoring model whether this is just an accident and a one-time incident or is it the beginning of a trend where you are unable to meet your future credit obligations. By continuing to make regular payments in the subsequent months you will be able to make your credit score bounced right back up to its original score. So being late by a day or even a couple of days will not have an impact on your credit score since it will probably not be reported on your credit history and even being late once will probably not impact your credit score that badly as long as you continue to make the future payments on time.
The damage that you will suffer is probably having to pay a late fee on the next billing cycle and the interest if your forget to pay your credit card bill for the entire billing cycle.