End of brake cable touches tire
It looks like it's been cut too short so can't be tucked out of the way.  But you may be able to cut it still shorter and use a smaller end cap/ferrule, or just part of one, or a blob of glue to stop the end fraying.

Bending the cable may work too -- you might not have enough length but a sharp bend away from the tyre might work.  Use longnose pliers.  This stopped my front derailleur cable irritating my leg, for example.

You're right to want to fix it -- metal rubbing on tyres isn't a good thing.