How severe is CVE-2026-84393?

CVE-2026-84393 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-84393 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-84393?

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.

When was CVE-2026-84393 published?

CVE-2026-84393 was published on 2026-09-08 and last updated on 2026-09-10.

CVE-2026-84393

CVE-2026-84393 is a high-severity vulnerability with a CVSS 3.x base score of 8.1. 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-297.

Key facts

Severity: High (CVSS 3.x base score 8.1)
EPSS exploit prediction: 0% (15th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-297
Published: 2026-09-08
Last modified: 2026-09-10

Description

A improper validation of certificate with host mismatch vulnerability in Fortinet FortiOS 7.6.1 through 7.6.6, FortiProxy 7.6.2 through 7.6.6 may allow attacker to information disclosure via <insert attack vector here>

Frequently asked questions

What is CVE-2026-84393?: A improper validation of certificate with host mismatch vulnerability in Fortinet FortiOS 7.6.1 through 7.6.6, FortiProxy 7.6.2 through 7.6.6 may allow attacker to information disclosure via <insert attack vector here>
How severe is CVE-2026-84393?: CVE-2026-84393 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-84393 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-84393?: 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.
When was CVE-2026-84393 published?: CVE-2026-84393 was published on 2026-09-08 and last updated on 2026-09-10.

References

https://fortiguard.fortinet.com/psirt/FG-IR-26-174

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CVE-2026-48144 — Critical (CVSS 9.1): Improper Validation of Certificate with Host Mismatch vulnerability in Apache Thrift c_glib bindings. This issue…
CVE-2025-68637 — Critical (CVSS 9.1): The Uniffle HTTP client is configured to trust all SSL certificates and disables hostname verification by default.…
CVE-2026-35563 — High (CVSS 8.5): It was identified that the LDAP client implementation in version 2.1.7 does not verify if the server certificate…
CVE-2025-3501 — High (CVSS 8.2): A flaw was found in Keycloak. By setting a verification policy to 'ALL', the trust store certificate verification is…

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