Critical Fortinet FortiMail Zero-Day: CVE-2026-104286 Enables Unauthenticated Arbitrary File Writes
In October 2026, CISA added CVE-2026-104286 to its Known Exploited Vulnerabilities (KEV) catalog, following reports of active exploitation targeting Fortinet FortiMail email security gateways. This CVSS 9.8 vulnerability arises from the intersection of improper pathname limitation (CWE-22) and improper neutralization of null bytes (CWE-158) within the web management interface. Unauthenticated attackers can leverage crafted HTTP requests containing path traversal sequences and null bytes to bypass directory restrictions, allowing arbitrary file writes outside the intended web root. This flaw enables remote code execution (RCE) through webshell deployment, potential credential theft from mailboxes, and subsequent lateral movement within corporate networks.
Fortinet SSL‑VPN RCE CVE-2022-42475 Exploited in PivotC2 RAT Campaigns
In mid‑September 2026 attackers exploited an unauthenticated stack‑based buffer overflow in Fortinet FortiOS SSL‑VPN (CVE‑2022-42475) affecting versions 6.4.x, 6.2.x, and 7.0.x prior to 7.0.11. A crafted POST to /remote/fgt_lang with directory‑traversal in the lang parameter triggers arbitrary code execution, allowing deployment of a web shell that downloads and executes the PivotC2 Remote Access Trojan. The malware establishes HTTP/S C2 to pivotc2‑update.net and secure‑sync.org, enabling credential harvesting, lateral movement via SMB/WMI, and further payload delivery across government, finance, healthcare, and energy sectors worldwide.