What is CVE-2020-12819?

CVE-2020-12819 is a medium-severity vulnerability in Fortinet Fortios, classified under Heap-based Buffer Overflow. CVSS score: 5.4/10. Published 2024-12-19.

How severe is CVE-2020-12819?

Medium severity. CVSS v3 base score is 5.4 out of 10.

Buffer overflow in Fortinet Fortios

CVE-2020-12819

A heap-based buffer overflow vulnerability in the processing of Link Control Protocol messages in FortiGate versions 5.6.12, 6.0.10, 6.2.4 and 6.4.1 and earlier may allow a remote attacker with valid SSL VPN credentials to crash the SSL VPN daemon by sending a large LCP packet, when tunnel mode is enabled. Arbitrary code execution may be theoretically possible, albeit practically very difficult to achieve in this context

Vulnerability class: Buffer Overflow

Published 2024-12-19 · last modified 2026-06-17.

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.

EPSS exploit prediction

EPSS: 0.008 (54.6th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 55th percentile — 54.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: +0.000

Affected products

Fortinet Fortios — versions 6.4.0, 6.2.0, 6.0.0

Weakness classification (CWE)

References

fortiguard.com/advisory/FG-IR-20-082 (Vendor Advisory)

Frequently asked questions

What is CVE-2020-12819?: CVE-2020-12819 is a medium-severity vulnerability in Fortinet Fortios, classified under Heap-based Buffer Overflow. CVSS score: 5.4/10. Published 2024-12-19.
How severe is CVE-2020-12819?: Medium severity. CVSS v3 base score is 5.4 out of 10.