What is CVE-2021-36194?

CVE-2021-36194 is a high-severity vulnerability in Fortinet Fortiweb, classified under Out-of-bounds Write. CVSS score: 8.8/10. Published 2021-12-09.

How severe is CVE-2021-36194?

High severity. CVSS v3 base score is 8.8 out of 10.

Buffer overflow in Fortinet Fortiweb

CVE-2021-36194

Multiple stack-based buffer overflows in the API controllers of FortiWeb 6.4.1, 6.4.0, and 6.3.0 through 6.3.15 may allow an authenticated attacker to achieve arbitrary code execution via specially crafted requests.

Vulnerability class: Buffer Overflow

Published 2021-12-09 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.014 (71.3th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 71st percentile — 71.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000

Affected products

Fortinet Fortiweb — versions FortiWeb 6.4.1, 6.4.0, and 6.3.0 through 6.3.15
Fortinet Fortiweb — versions 6.4.0, 6.4.1

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

fortiguard.com/advisory/FG-IR-21-152 (Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2021-36194?: CVE-2021-36194 is a high-severity vulnerability in Fortinet Fortiweb, classified under Out-of-bounds Write. CVSS score: 8.8/10. Published 2021-12-09.
How severe is CVE-2021-36194?: High severity. CVSS v3 base score is 8.8 out of 10.