‼️ One Forged Header: Unauthenticated Authentication Bypass in Fortinet FortiClient EMS (CVE-2026...
Fortinet FortiClient EMS unauthenticated authentication bypass via forged header (CVE-2026-35616)
Run Fortinet?
Get an email when a reviewed story names Fortinet, usually within the hour.
Free. Your list stays private and never appears in a subject line. One click stops it. How Vendor Watch worksPrivacy
Summary
A critical authentication bypass vulnerability has been discovered in Fortinet FortiClient EMS that allows unauthenticated attackers to bypass authentication using a forged HTTP header. The vulnerability (CVE-2026-35616) enables unauthorized access to the management interface without valid credentials. This represents a significant security risk for organizations using FortiClient EMS for endpoint management.
The lesson from this incident
Full lessonA critical vulnerability in Fortinet FortiClient EMS allows attackers to bypass authentication entirely by manipulating HTTP headers, granting unauthorized access to management interfaces without any credentials. This flaw demonstrates how improper input validation and weak authentication mechanisms can create catastrophic security gaps in enterprise management systems. Organizations using affected versions face immediate risk of complete system compromise, as attackers can gain administrative control over endpoint management infrastructure through a simple header manipulation attack.
What helps against this
How we list vendors
- Identity threat detection and response (ITDR)
Attackers who log in with real, stolen credentials get noticed.
- Automated patch management
Known holes get closed in days, not months.
- Device management (MDM and UEM)
Every company laptop and phone is known, encrypted, locked down and up to date.
Indicators of Compromise
- cve — CVE-2026-35616