
Critical FortiMail Zero-Day CVE-2026-104286 Exploited in Active Attacks
In October 2026, Fortinet disclosed CVE-2026-104286, a critical path traversal vulnerability in FortiMail with a CVSS score of 9.8. The flaw allows unauthenticated attackers to write arbitrary files on vulnerable systems through crafted HTTP requests, affecting FortiMail versions 7.2.0-7.2.9, 7.4.0-7.4.8, 7.6.0-7.6.6, and 8.0.0-8.0.1. Attackers actively exploited this zero-day to deploy malicious libraries, modify system binaries, and establish data exfiltration channels to remote servers at compromised IP addresses. This incident highlights the growing trend of attackers targeting email security appliances as high-value entry points into enterprise networks, particularly exploiting path traversal vulnerabilities that bypass authentication mechanisms and enable immediate system-level access.
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