⚠ Actively exploited in ransomware campaigns
This vulnerability is on the CISA Known Exploited Vulnerabilities list and has been used in known ransomware attacks. CISA required action: Apply updates per vendor instructions.. Due date: 2022-05-03.

CVE-2020-12812 — Improper Handling of Case Sensitivity in Fortinet Fortios

CWE-178 — Improper Handling of Case SensitivityCWE-287 — Improper Authentication10 documents9 sources
Severity
9.8CRITICALNVD
EPSS
48.5%
top 2.24%
CISA KEV
KEVRansomware
Added 2021-11-03
Due 2022-05-03
Exploit
Exploited in wild
Active exploitation observed
Affected products
2
Fortinet FortiosFortinet Fortios
Timeline
PublishedJul 24
KEV addedNov 3
KEV dueMay 3
Latest updateJan 2
CISA Required Action: Apply updates per vendor instructions.

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 vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitability: 3.9 | Impact: 5.9

Affected Packages2 packages

▶NVDfortinet/fortios6.2.0 — 6.2.4+2
▶CVEListV5fortinet/fortinet_fortiosFortiOS 6.4.0, 6.2.0 to 6.2.3, 6.0.9 and below

🔴Vulnerability Details

3
GHSA
GHSA-r9cj-q2hj-hfq9: An improper authentication vulnerability in SSL VPN in FortiOS 6↗2022-05-24
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CVEList
CVE-2020-12812: An improper authentication vulnerability in SSL VPN in FortiOS 6↗2020-07-24
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VulnCheck
Fortinet FortiOS SSL VPN Improper Authentication Vulnerability↗2020
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📋Vendor Advisories

2
CISA
Fortinet FortiOS SSL VPN Improper Authentication Vulnerability↗2021-11-03
▶
Fortinet
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 us...↗2020-07-24
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🕵️Threat Intelligence

3
Bleepingcomputer
Over 10K Fortinet firewalls exposed to actively exploited 2FA bypass↗2026-01-02
▶
Bleepingcomputer
Fortinet warns of 5-year-old FortiOS 2FA bypass still exploited in attacks↗2025-12-29
▶
Fortinet
Product Security Advisory and Analysis: Observed Abuse of FG-IR-19-283 | Fortinet Blog↗2025-12-24
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CVE-2020-12812 — Improper Handling of Case Sensitivity | cvebase