Snipe-IT before 8.7.0 Arbitrary File Read and SSRF via Markdown

Snipe-IT before 8.7.0 fails to properly sanitize markdown image syntax in note fields, allowing authenticated users to read arbitrary server files and issue server-side HTTP requests. Attackers can submit markdown image syntax in checkout acceptance notes that survive HTML escaping, are expanded by CommonMark parser, and resolved by laravel-mail-auto-embed via file_get_contents or curl, exfiltrating sensitive files like .env containing APP_KEY.