Is CVE-2020-12812 in the CISA KEV catalog?

Yes. CVE-2020-12812 is on the CISA Known Exploited Vulnerabilities list, added 2021-11-03, and has known ransomware campaign use.

What is the CVSS severity of CVE-2020-12812?

CVE-2020-12812 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2020-12812?

CVE-2020-12812 has an EPSS score of 49.34% (99th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2020-12812?

Upgrade fortios to 6.2.4 or later.

CVE & CISA-KEV Catalog

CVE-2020-12812

CRITICALCISA KEVEPSS 99th pctl

9.8

CVSS v3

NVD

Description

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.

CWE-178 CWE-287Improper Authentication

How to fix

Remediation Available

fortiosNVD

Affected:>= 6.2.0, < 6.2.4Fixed in:6.2.4CVE-2020-12812derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

49.34%probability of exploitation in 30 days

99thpercentile

Very high risk: more likely to be exploited than 99% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

Fortinet FortiOS SSL VPN Improper Authentication Vulnerability

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.

Apply updates per vendor instructions.

Remediation due: 2022-05-03

Associated with ransomware campaigns

References

Vendor Advisory1

fortiguard.com

Government Resource1

cisa.gov

Related Vulnerabilities

Other CWE-178 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-27636	Medium	5.6	80%	-	Fix
CVE-2021-24347	High	8.8	52%	-	Fix
CVE-2003-0411	High	7.5	25%	-	-
CVE-2018-9845	Critical	9.8	13%	-	Fix
CVE-2001-0766	Critical	9.8	8.2%	-	-
CVE-1999-0239	High	7.5	7.4%	-	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-10-24.