CVE-2026-93405 Mailspring: Stored XSS in attachment quick preview (unsanitized Markdown/DOCX/XLSX conversion)

Mailspring is a fast, cross-platform, open-source email client. Prior to 1.17.0, attachment quick preview converts Markdown, DOCX, and XLSX attachments with Snarkdown, Mammoth, and SheetJS and inserts the resulting HTML into the preview document through innerHTML without sanitization. A remote...