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

Published Jul 24, 2020
·
Updated

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.

Other sources

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.

CISA

Affected Software

4 affected components
Fortinet FortiOS
Fortinet FortiOS<6.0.10
Fortinet FortiOS>=6.2.0<6.2.4
Fortinet FortiOS=6.4.0

Event History

Jul 24, 2020
CVE Published
via MITRE·10:28 PM
Data Sourced
via MITRE·10:28 PM
DescriptionWeakness
Data Sourced
via NVD·11:15 PM
DescriptionSeverityWeaknessAffected Software
Nov 3, 2021
Known Exploited
via CISA·12:00 AM
Known Ransomware
via CISA·12:00 AM
Jun 4, 2025
News Published
via The Register·11:40 PM
News Published
via The Register·11:45 PM
Dec 29, 2025
News Published
via BleepingComputer·11:16 AM
News Published
via BleepingComputer·11:17 AM
Jan 2, 2026
News Published
via BleepingComputer·04:01 PM

Peer vulnerabilities

Found alongside the following vulnerabilities.

Free Weekly Intel

Don't miss critical vulnerabilities

Join thousands of security professionals who receive our weekly digest of trending CVEs, zero-days, and exploited vulnerabilities.

No spam. Unsubscribe anytime.

Frequently Asked Questions

1

What is the severity of CVE-2020-12812?

CVE-2020-12812 is classified as a high severity vulnerability.

2

How do I fix CVE-2020-12812?

To fix CVE-2020-12812, upgrade FortiOS to version 6.0.10 or higher, or to versions 6.2.4 or later.

3

What software versions are affected by CVE-2020-12812?

CVE-2020-12812 affects FortiOS versions 6.0.9 and below, 6.2.0 to 6.2.3, and 6.4.0.

4

What type of vulnerability is CVE-2020-12812?

CVE-2020-12812 is an improper authentication vulnerability in SSL VPN.

5

Can users bypass the second factor of authentication due to CVE-2020-12812?

Yes, users may bypass the second factor of authentication by changing the case of their username.

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203