CVE-2020-12812
Fortinet FortiOS SSL VPN Improper Authentication Vulnerability
MITRE ATT&CK techniques
How this vulnerability maps to adversary behaviour, from the Center for Threat-Informed Defense's public CVE→ATT&CK mappings. Use it to check whether your detections already cover the technique.
Summary
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.
Affected software
Vendor: Fortinet · Product: FortiOS
Weakness types (CWE):
What to do
This vulnerability appears in CISA's Known Exploited Vulnerabilities catalog, meaning it is being exploited in the wild. Prioritize patching affected systems and verify exposure across your estate.
Related vulnerabilities in Fortinet
| CVE | Name | EPSS | Exploited |
|---|---|---|---|
| CVE-2018-13379 | Fortinet FortiOS SSL VPN Path Traversal Vulnerability | 100.0% | Yes |
| CVE-2022-40684 | Fortinet Multiple Products Authentication Bypass Vulnerability | 100.0% | Yes |
| CVE-2022-42475 | Fortinet FortiOS Heap-Based Buffer Overflow Vulnerability | 99.5% | Yes |
| CVE-2024-55591 | Fortinet FortiOS and FortiProxy Authentication Bypass Vulnerability | 98.3% | Yes |
| CVE-2023-48788 | Fortinet FortiClient EMS SQL Injection Vulnerability | 97.6% | Yes |
| CVE-2025-25257 | Fortinet FortiWeb SQL Injection Vulnerability | 96.7% | Yes |
| CVE-2024-47575 | Fortinet FortiManager Missing Authentication Vulnerability | 94.8% | Yes |
| CVE-2026-21643 | Fortinet FortiClient EMS SQL Injection Vulnerability | 94.1% | Yes |
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