How severe is CVE-2026-21743?

CVE-2026-21743 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-21743 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-21743?

CVE-2026-21743 affects Fortinet Fortiauthenticator. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-21743?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-21743 have an EU (EUVD) identifier?

Yes. CVE-2026-21743 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-6220.

When was CVE-2026-21743 published?

CVE-2026-21743 was published on 2026-02-10 and last updated on 2026-06-17.

CVE-2026-21743

CVE-2026-21743 is a high-severity vulnerability in Fortinet Fortiauthenticator with a CVSS 3.x base score of 7.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-862.

Key facts

Severity: High (CVSS 3.x base score 7.2)
EPSS exploit prediction: 0% (27th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-6220
Weakness: CWE-862
Affected product: Fortinet Fortiauthenticator
Published: 2026-02-10
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2026-21743?: CVE-2026-21743 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-21743 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-21743?: CVE-2026-21743 affects Fortinet Fortiauthenticator. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-21743?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-21743 have an EU (EUVD) identifier?: Yes. CVE-2026-21743 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-6220.
When was CVE-2026-21743 published?: CVE-2026-21743 was published on 2026-02-10 and last updated on 2026-06-17.

References

https://fortiguard.fortinet.com/psirt/FG-IR-25-528

Affected products (1)

cpe:2.3:a:fortinet:fortiauthenticator:*:*:*:*:*:*:*:*

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