My vote goes for huntsman spider, and a male one at that, but I can't say which species. Will have a quick lookup and see if I can narrow it down for you
It's hard to say given I don't have a clear list of Vietnam spiders but this is a Sparassidae, ( a huntsman), and as for family some possibilities are Sinopoda, Rhithymna, Pseudopoda, and Heteropoda.
When I first moved here and saw one I freaked out and begged my husband to catch it. He laughed and said they are good spiders, and very fast so hard to catch anyway.
That spider lived above the window blinds, and I realised I would have to sweep the dead bugs off the windowsill every few days.
I'm no expert, but looking up Vietnamese spiders, it could be a huntsman?
Disclaimer: I know nothing more than the average person on spiders, it may be harmful, it may not be a huntsman. I would advise caution until someone who knows more that I can identify it.
I am not an expert, so do not take what I say for "should I let this thing bite me", but in Washington and the UK we have "giant house spiders" that look just like this (to my non trained eye). They are terrifying to find, but harmless generally. Leave very waxy webs.
If that's the case, just start putting out some sticky traps in your home, wherever you find one just throw a trap down. Warmer years brings more of them
You're going to get next to no help at all without a location, and even with a location there's not really enough detail in the photo for a good identification.
People will need to know what country you live in, what region of said country if it's a larger one like the United States or Australia, but even with that information you're only going to get guesses because you really can't see identifying features on the spider in this photo.