What is CVE-2026-21743?

CVE-2026-21743 is a high-severity vulnerability in Fortinet Fortiauthenticator, classified under Missing Authorization. CVSS score: 7.2/10. Published 2026-02-10.

How severe is CVE-2026-21743?

High severity. CVSS v3 base score is 7.2 out of 10.

Auth bypass in Fortinet Fortiauthenticator

CVE-2026-21743

A missing authorization vulnerability in Fortinet FortiAuthenticator 6.6.0 through 6.6.6, FortiAuthenticator 6.5 all versions, FortiAuthenticator 6.4 all versions, FortiAuthenticator 6.3 all versions may allow a read-only user to make modification to local users via a file upload to an unprotected endpoint.

Vulnerability class: Broken Access Control

Published 2026-02-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (30.3th percentile), scored 2026-10-20.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 30.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.000

Affected products

Fortinet Fortiauthenticator — versions 6.6.0, 6.5.0, 6.4.0

Weakness classification (CWE)

CWE-862 — Missing Authorization

References

fortiguard.fortinet.com/psirt/FG-IR-25-528 (Vendor Advisory)

Frequently asked questions

What is CVE-2026-21743?: CVE-2026-21743 is a high-severity vulnerability in Fortinet Fortiauthenticator, classified under Missing Authorization. CVSS score: 7.2/10. Published 2026-02-10.
How severe is CVE-2026-21743?: High severity. CVSS v3 base score is 7.2 out of 10.