I've found that I can narrow it down similar to bug #63365: As long as I
don't compile src/sysdep.c with -D_FORTIFY_SOURCE, the resulting
binaries seem to behave normally. Does that maybe suggest an upstream
problem? I compiled it as follows:

git clean -xdf
git checkout emacs-28.2
./autogen.sh
./configure
cd src
make sysdep.o CFLAGS='-g3 -O2 -gdwarf-2 -Wp,-D_FORTIFY_SOURCE=2'
make sysdep.o -W sysdep.c
cd ..
make CFLAGS='-g3 -O2 -gdwarf-2 -Wp,-D_FORTIFY_SOURCE=2'

I've attached the objects as well as their dumps in case anyone wants to
take a look.