CVE-2020-12812
critical CISA KEVFortinet FortiOS SSL VPN Improper Authentication Vulnerability
Vendor / product: Fortinet — FortiOS
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
9.8
9.8 (CVSS v3.1)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Severity source: NVD CVSS v3.1 (nvd@nist.gov)
Timeline (UTC)
Published: 2020-07-24 23:15
Modified: 2026-10-02 14:54
NVD status: Analyzed
Last synced 2 days ago
Verified against the source API 2026-10-27 07:07 UTC
Exploitation
Listed in CISA KEV
Added 2021-11-03 · due 2022-05-03
Known ransomware use: Known
Required action (CISA)
Apply updates per vendor instructions.
Affected products
fortinet / fortios <6.0.10, ≥6.2.0 <6.2.4, 6.4.0
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
Vendor advisory: https://fortiguard.com/psirt/FG-IR-19-283
Vendor advisory: https://fortiguard.com/psirt/FG-IR-19-283
References
- https://fortiguard.com/psirt/FG-IR-19-283 psirt@fortinet.com
- https://fortiguard.com/psirt/FG-IR-19-283 af854a3a-2127-422b-91ae-364da2661108
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-12812 134c704f-9b21-4f2e-91b3-4a467353bcc0
Data sources
CISA KEV — fetched 2026-10-27 06:50 UTC · record ↗
NVD CVE API 2.0 — fetched 2026-10-27 07:07 UTC · record ↗