CVE-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.
Key facts
- CVSS score
- 9.8 (v3.1)
- Severity
- CRITICAL
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
- CWE-178
- EPSS score
- 45.4% (99th percentile)
- In CISA KEV
- Yes, added November 3, 2021
- In EU EUVD
- Yes (EUVD-2020-5095)
- Published
- July 24, 2020
- NVD last modified
- October 2, 2026
- Status
- Analyzed
CISA Known Exploited Vulnerability
Fortinet FortiOS SSL VPN Improper Authentication Vulnerability
Added to the KEV catalog on November 3, 2021; federal remediation due May 3, 2022. Known to be used in ransomware campaigns.
EU Vulnerability Database (EUVD)
This vulnerability is also tracked by ENISA as EUVD-2020-5095 in the EU Vulnerability Database. ENISA flags it as known exploited. Last updated in EUVD on October 1, 2026.
View on the EU Vulnerability DatabaseAffected products
- fortinet / fortios
- fortinet / fortios
Certified products that may be affected
4 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.
- FortiOS 5.6 - Fortinet, Inc. - FIPS 140 3639 - historical
- FortiOS 5.2 - Fortinet, Inc. - FIPS 140 2765 - historical
- FortiOS™ - Fortinet, Inc. - FIPS 140 1754 - historical
- FortiOS - Fortinet, Inc. - FIPS 140 1431 - historical
References
- https://fortiguard.com/psirt/FG-IR-19-283(Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-12812(US Government Resource)
Last updated October 4, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS
Query CVEs from your AI assistant
The CVE/NVD Explorer brain answers CVE questions directly inside Claude, ChatGPT, or any MCP assistant — always up to date, no setup. Add it once and stop pasting advisories into chat.
Add the CVE brain