Buffer overflow in Fortinet Fortios
CVE-2020-12820
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.
Vulnerability class: Buffer Overflow
EPSS: 0.009 (54.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L.
Affected products
- Fortinet Fortios — versions 6.0.0, 5.6.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- psirt@fortinet.com (Vendor Advisory)
Frequently asked questions
- What is CVE-2020-12820?
- CVE-2020-12820 is a medium-severity vulnerability in Fortinet Fortios, classified under Stack-based Buffer Overflow. CVSS score: 5.4/10. Published 2024-12-19.
- How severe is CVE-2020-12820?
- Medium severity. CVSS v3 base score is 5.4 out of 10.
- Is CVE-2020-12820 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.