The ACME-challenge endpoint in Appwrite 0.5.0 up to and including 0.12.x prior to 0.12.2 allows remote malicious users to read arbitrary local files via ../ directory traversal. In order to be vulnerable, APP_STORAGE_CERTIFICATES/.well-known/acme-challenge must exist on disk. (This pathname is automatically created if the user chooses to install Let's Encrypt certificates via Appwrite.)
Vulmon