CVE-2026-104286: Critical FortiMail Zero-Day Exploited for Unauthenticated File Writes

**CVE-2026-104286 — FortiMail critical zero-day exploited in the wild:** Fortinet disclosed a 9.8 CVSS FortiMail vulnerability enabling unauthenticated arbitrary file writes via path traversal and NULL-byte issues; exploitation has been observed in the wild and the flaw was added to CISA’s Known Exploited Vulnerabilities catalog, with vendor mitigations (disable IBE, remove or restrict internet-facing management, and upgrade to fixed builds) and published IOCs and detection guidance for incident assessment and hunting.