This is a close matchup for If someone knows your wifi password can they hack your router?
I gave someone my general (not the guest-specific) wifi password, but they flew home to another continent. My partner is concerned about whether that's a risk. I have no reason to suspect the person of anything, but I can't vouch for them either - my kid knows them, I don't.
Assume a modern home router with the default admin password changed. The router has not been specially configured to allow remote configuration. Assume also that the person knowing the password may have saved the router's ISP-issued IP.
Does the fact that the "attacker" is out of wifi range alter the answers given to that question? (be mindful of badly configured network, unchanged admin passwords, etc...) However it seems to me basic security practices would be to just ignore wifi credentials entirely when the router is accessed from the internet.
In theory I guess the attacker could give your credentials to someone local who could then do their bad stuff on wifi. In my case however, I live in a high rise, with strict elevator access controls.
p.s. Yes, yes, I may just end up changing the password. But what are risks if I don't?