I mean, it would most likely affect any software that uses libwebp. Taking a quick look at Arch's libwebp page:

* allegro

* emacs (lmao)

* ffmpeg

* freeimage

* gd (required for gnuplot, fceux, graphviz, etc)

* godot

* openimageio

* qt5/6-imageformats

* sdl2_image

* thunderbird

* webkit2gtk

* etc

optionally:

* gdal

* imagemagick

* python-pillow

* python-piexif

* etc

Should note that a vuln doesn't mean an exploit, of course.