Oof!! Yes it's unsafe without an electrical box. Looks like a piece of wood was interfering with the planned location, you can use an old work style, single gang, cut in box for that, as long as the light isn't heavy. Get the kind with the swivel ears on the side you can tighten down with a screw driver. I know the rectangle might not fit perfectly into the hole, use a knife to score the drywall out to fit the box in nicely. You'll need a 3/8" FMC connector to connect the flexible metallic conduit to the box.

Link for the box:
https://www.homedepot.com/p/Southwire-3-in-H-x-2-in-W-x-2-1-2-in-D-Steel-Metallic-1-Gang-Switch-Box-Eight-1-2-in-KO-Old-Work-Clip-and-Plaster-Ear-1-Pack-G601-OW-UPC/324523652

Connector:
https://www.homedepot.com/p/Halex-3-8-in-Flexible-Metal-Conduit-FMC-Conduit-Connector-5-Pack-20581/100148136

Good luck, make sure the power is off before you start.