Improper Authentication in FortiOS - CVE-2020-12812
Published: July 16, 2020 / Updated: January 5, 2026
Vulnerability identifier: #VU30135
CSH Severity: High
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2020-12812
CWE-ID: CWE-287
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vulnerability details
The vulnerability allows a remote attacker to bypass authentication process.
The vulnerability exists due to an error in when processing authentication requests in SSL VPN. A remote authenticated attacker can changed the case of their username and gain unauthorized access to the application without being prompted for the second factor of authentication (FortiToken).
Affected software
FortiOS
How to mitigate CVE-2020-12812
Install updates from vendor's website.
FortiOS - addressed in versions 6.0.10, 6.2.4, 6.4.1