Highly exploitable, CVE-2026-21743 poses a critical security risk that could lead to severe breaches.
Status: Analyzed
Last updated: 🕓 12 Feb 2026, 16:05 UTC
Originally published on: 🕓 10 Feb 2026, 16:16 UTC
Time between publication and last update: 1 days
CVSS Release: version 3
psirt@fortinet.com
Secondary
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
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.
The exploitability of CVE-2026-21743 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
The exploitability of CVE-2026-21743 is influenced by multiple factors. Security teams should analyze system configurations and apply appropriate countermeasures to mitigate threats.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2026-21743, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2026-21743, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
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