CVE DATABASE / CVE-2020-12812
CVE-2020-12812
Fortinet FortiOS SSL VPN Improper Authentication Vulnerability
CVSS 9.8 · CRITICAL
⚠ CISA KEV — ACTIVELY EXPLOITED
RANSOMWARE
On the CISA KEV catalog
Confirmed exploited in the wild. Added 2021-11-03.
Federal remediation due 2022-05-03.
Required action: Apply updates per vendor instructions.
Summary
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.
CVSS 3.1 breakdown
| Base score | 9.8 (CRITICAL) |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| Attack vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity | HIGH |
| Availability | HIGH |
Weakness type (CWE)
Affected products
Fortinet fortios
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References
- https://fortiguard.com/psirt/FG-IR-19-283
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-12812
Data: NIST NVD + CISA KEV. NVD last modified 2025-10-24. Always verify against the vendor advisory before acting.