How Cloudflare Images addressed the aCropalypse vulnerability
Acropalypse (CVE-2023-21036) is a vulnerability caused by image editing tools failing to truncate images when editing has made them smaller, most often seen when images are cropped. This leaves remnants of the cropped contents written in the file after the image has finished. The remnants (written in a ‘trailer’ after the end-of-image marker) are ignored by most software when reading the image, but can be used to partially reconstruct the original image by an attacker.