CVE-2020-12812—Fortinet FortiOS SSL VPN Improper Authentication Vulnerability

Vulnerability Name

Fortinet FortiOS SSL VPN Improper Authentication Vulnerability

Description

Fortinet FortiOS SSL VPN contains an improper authentication vulnerability that may allow a user to login successfully without being prompted for the second factor of authentication (FortiToken) if they change the case in their username.

Known To Be Used in Ransomware Campaigns?

Ransomware Status:

KNOWN

Action

Apply updates per vendor instructions.

Additional Notes

• https://nvd.nist.gov/vuln/detail/CVE-2020-12812

Related News Articles

• Over 10K Fortinet firewalls exposed to actively exploited 2FA bypassJanuary 2, 2026
• Fortinet warns of 5-year-old FortiOS 2FA bypass still exploited in attacksDecember 29, 2025
• Fortinet Warns of Active Exploitation of FortiOS SSL VPN 2FA Bypass VulnerabilityDecember 25, 2025

Related Weaknesses

• CWE-178
• CWE-287