Not commenting on anything else in the music, my first reaction is: the harmonizing voice moves in parallel with the subject, that's a counterpoint/voice leading problem with the harmonizing voice. Change the harmonizing voice(s.)
Being passing tones mitigates the problem somewhat, but the fact they are in the outer voices is a problem.
Sometimes the way out of parallel/direct motions looking for the minimum voice leading change to get another relative motion. In other words, if the harmony is good, keep it and change one of the parts to get contrary or oblique motion. Probably best to keep strong beat harmonies as it and try to make the change on a weak beat (or whatever seems a subordinate harmony.)
wouldn't making the neighboring motion contrary and then delaying the move from
G#5 up to
...everything seems mostly the same, but the parallel movement is removed.
I suppose this is even the simplest...
...sort of an escape tone from
G#5 then up to
I'm not sure I agree with the comment in the accepted answer that the parallel octaves are OK because it's the surface, melodic detail of the harmonic skeleton. I've always had the impression the attitude was the other way around. Skeletal harmony in parallel motion can be glossed over with disguising melodic motion. Here is an example I like from L. Mozart's Nannerl Notenbuch...
...Red highlights the parallel fifths in the harmonic skeleton, blue highlights the "disguising" melodic to intervening thirds. I've seen that kind of thing rather than parallel melodic motion in outer voices.
And of course we aren't talking about instrumental doubling at the octave.