CISA KEV catalog
Confirmed active exploitation.
Listed in CISA's catalog of Known Exploited Vulnerabilities: attackers are using it in real attacks. Patch it with priority.
- Name
- Fortinet FortiOS SSL VPN Improper Authentication Vulnerability
- Added to catalog
- Remediation due date (US federal)
- Required action
- Apply updates per vendor instructions.
Description
An improper authentication vulnerability in SSL VPN in FortiOS 6.4.0, 6.2.0 to 6.2.3, 6.0.9 and below may result in a user being able to log in successfully without being prompted for the second factor of authentication (FortiToken) if they changed the case of their username.
Affected products
fortinet: fortios
References3
- fortiguard.com/psirt/FG-IR-19-283 Vendor Advisory
- fortiguard.com/psirt/FG-IR-19-283 Vendor Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=… US Government Resource
Metrics
- CVSS 3.1
-
9.8
CRITICAL
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 45% percentile: 99 · as of 2 November 2026
- CWE
- CWE-178CWE-287