Chrome was updated September 11
Matrix Element Desktop updated September 15, without a changelog or advisory. (The Element update on September 13 did not include the updated electron with the fix; today’s update does, according to their announcement on Matrix.)
Many/most electron apps don’t receive timely security updates, so if you don’t want arbitrary images to be able to get code execution you might want to stop using them.
I only use Bromite at this point for some streaming stuff which don’t work so well on FF based browsers, and Mulch always pauses playback when minimised… Bloody annoying. I didn’t want to use Brave, but I guess I might have to try it.