CVE-2026-21741 Fortinet CVE debrief

Who should care

Defenders responsible for Fortinet FortiNAC-F systems should assess exposure and prioritize patching to prevent potential phishing attacks and unauthorized website redirection. This includes reviewing compensating controls, monitoring for suspicious activity, and verifying affected versions. Security teams and vulnerability management teams should also review the CVE record and vendor advisory to validate affected scope, severity, and vendor guidance.

Why it matters

CVE-2026-21741 is a low-severity Open Redirect vulnerability in Fortinet FortiNAC-F. While exploitation requires a privileged attacker, defenders should still prioritize patching and verifying affected versions to prevent potential phishing attacks and unauthorized website redirection.

• Potential for phishing attacks via open redirects
• Risk of unauthorized website redirection
• Need for verification of affected versions
• Priority for patching and mitigation

Technical summary

CVE-2026-21741 is an Open Redirect vulnerability in Fortinet FortiNAC-F versions 7.2.0 through 7.6.5. A remote privileged attacker with system administrator role may redirect users to an arbitrary website via crafted CSV file. This vulnerability is classified under CWE-601 and has a CVSS score of 2.4, indicating a low severity. However, defenders should still prioritize patching and verifying affected versions to prevent potential phishing attacks and unauthorized website redirection. The vulnerability affects Fortinet FortiNAC-F 7.6.0 through 7.6.5, 7.4 all versions, and 7.2 all versions.

Defensive priority

Defenders should prioritize verifying and patching affected FortiNAC-F versions.

Recommended defensive actions

• Verify and patch affected FortiNAC-F versions
• Restrict access to FortiNAC-F systems
• Monitor for suspicious activity
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

Evidence from the CVE Program and NVD suggests an Open Redirect vulnerability exists in Fortinet FortiNAC-F versions 7.2.0 through 7.6.5. A remote privileged attacker with system administrator role may redirect users to an arbitrary website via crafted CSV file. The CVE Program and NVD provide official records of this vulnerability, which has not been modified since its publication on 2026-04-14T16:16:35.777Z.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.