ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2020-12812

Fortinet FortiOS SSL VPN Improper Authentication Vulnerability

Published Jul 24, 2020 · catalog updated Oct 2, 2026 · Fortinet FortiOS

Patch now

CVE-2020-12812 is in the CISA known-exploited catalog, due May 3, 2022. Confirm Fortinet FortiOS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Critical9.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
45.38%
Remediation
Remediation guidance
Affected products
cpe fortinet/fortios · vendor 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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe fortinet/fortios6.4.0
  • vendor Fortinet FortiOSversion unspecified

How to fix CVE-2020-12812

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2020-12812 is in the CISA known-exploited catalog, due May 3, 2022. Confirm Fortinet FortiOS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with 6.4.0. Apply updates per vendor instructions.

What should an analyst verify?

CWE-178; CWE-287: Improper Authentication. EPSS 45.38%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Fortinet security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jul 24, 2020 · Catalog

    Detected

    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.

  2. Nov 3, 2021 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. May 3, 2022 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Oct 2, 2026 · Catalog

    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.

Sources

  • CISA KEVConfirmed exploitationCVE-2020-12812

    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.gov
  • CVE.orgVulnerability recordCVE-2020-12812

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2020-12812

    30-day exploitation probability 45.4%

    first.org
  • NIST NVDVulnerability recordCVE-2020-12812

    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.

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2020-12812

    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.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.