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CVE-2020-12812

Fortinet FortiOS SSL VPN Improper Authentication

9.8 CRITICALActively exploited (CISA KEV)Used in ransomwareEPSS 45.4%
  1. Published24 Jul 2020
  2. Added to CISA KEV3 Nov 2021
  3. Remediation due3 May 2022
Actively exploited (CISA KEV)

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.

Added to KEV: 3 Nov 2021Federal remediation due: 3 May 2022Used in ransomware

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Fortinet FortiOS≥ 6.2.0 < 6.2.4 · < 6.0.10 · 6.4.0

Remediation

Fixed in
Fortinet FortiOS≥ 6.2.4

References

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Frequently asked

Is CVE-2020-12812 being actively exploited?

Yes. CVE-2020-12812 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 3 Nov 2021. It has been used in ransomware campaigns.

How severe is CVE-2020-12812?

CVE-2020-12812 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 45.4% probability of exploitation.

Which products are affected by CVE-2020-12812?

Affected products include Fortinet FortiOS.

How do I fix CVE-2020-12812?

Upgrade affected software to a fixed version, for example Fortinet FortiOS 6.2.4 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2020-12812 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, a risk for it never ranks below high, and the update that fixes it moves to the Emergency patch lane. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.