During the Oscars, knowing that it would be a highly televised award show with top actors and celebrities are kidnapped and held hostage by the Russian Mafia demanding the release of their crime boss who has been detained in the US. A stuntman in attendance and a famous actress whom he had dated previously must help in rescuing all the hostages including his mom who he brought to the award ceremony.

Stuntman was mentioned as an example or without thinking it through. To really do it, consider if his presence needs an explanation since he wouldn't be invited by the Academy. If anything, the stuntman would be someone else's plus-one. Or he'd be outside protesting (with others, seeking recognition) and somehow sneak in when all hell breaks loose.

You're welcome. While it's better to have too much than too little, the next version of the logline can be shorter.

>> knowing that it would be a highly televised award show with top actors and celebrities

Cut. Part of saying Oscars (or any show) is the understanding of the quoted part. Better you try to trim the rest.

>> including his mom who he brought to the award ceremony.

This is good. Aside from the obvious personal stakes, it can help with a possible theme of 'Is a celebrity's life more valuable than a civilian's?' Though thinking of that for a few moments makes me wonder if it would be better to have fewer hostages. Going further, a couple of actors, a couple of singers, etc., and this way there's the deeper question of 'Is one entertainer's life more valuable than another?' (I figure it's better to share such thoughts, take 'em or leave 'em as you wish.)

It's also good that the leads have a little conflict between them (that came to mind afterwards!). However, what does "famous actress" do for the story? Picturing Jennifer Lawrence as herself is more confusing or flat than cool or funny. The only thing that comes to mind right away is that she's on a bad streak and out to save, say, a director who's next movie she desperately wants to be in.

Either clarifying the female lead or adjusting another word or three can help with the tone, action or action-comedy. I assume it's the latter.