What’s Vulnerable › Vulnerabilities
CVE-2020-12820
- Severity: high (CVSS 8.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.9% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2024-12-19 · updated 2026-06-17
- Weakness: CWE-121
Description
Under non-default configuration, a stack-based buffer overflow in FortiOS version 6.0.10 and below, version 5.6.12 and below may allow a remote attacker authenticated to the SSL VPN to crash the FortiClient NAC daemon (fcnacd) and potentially execute arbitrary code via requesting a large FortiClient file name. We are not aware of proof of concept code successfully achieving the latter.
Affected products
- Fortinet FortiOS (FortiGate): before 5.6.13; from 6.0.0 before 6.0.11 — fixed in 5.6.13, 6.0.11
How to fix
Upgrade to a fixed version: Fortinet FortiOS (FortiGate) 5.6.13, 6.0.11. Check the vendor advisory for mitigations.
References
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