Fortinet FortiOS vulnerabilities and fixes

CVEs that mention Fortinet FortiOS, ranked by priority. 5 tracked.

Fortinet FortiOS has 5 tracked vulnerabilities, 1 critical and 3 exploited in the wild (CISA KEV). A fixed release or vendor patch exists for 5. Most recent: 2026-08-12. Highest priority: CVE-2024-21762 (score 100/100).

• CVE-2024-21762 CRITICAL 9.8 EXPLOITED UPGRADE UPGRADE Fortinet FortiOS Out-of-Bound Write Vulnerability
• CVE-2025-25249 HIGH 8.1 EXPLOITED UPGRADE UPGRADE Fortinet Multiple Products Heap-based Buffer Overflow Vulnerability
• CVE-2025-61624 MEDIUM 6.0 EXPLOITED UPGRADE UPGRADE Fortinet Multiple Products Path Traversal Vulnerability
• CVE-2026-71407 MEDIUM 5.6 UPGRADE A Stack-based Buffer Overflow vulnerability [CWE-121] vulnerability in Fortinet FortiOS 7.6.1 through 7.6.6 ma
• CVE-2026-71408 MEDIUM 5.3 UPGRADE A allocation of resources without limits or throttling vulnerability in Fortinet FortiOS 7.6.0 through 7.6.6,

FAQ

How do I fix Fortinet FortiOS vulnerabilities?

Open the CVE for your version, check the affected range, then follow the listed action: upgrade to the fixed release, or downgrade or mitigate if no fix exists yet. Commands for each OS are shown on every CVE page.

Is Fortinet FortiOS being exploited right now?

Yes: 3 Fortinet FortiOS CVEs are on the CISA Known Exploited Vulnerabilities list, so patch those first.

Which Fortinet FortiOS CVE should I patch first?

CVE-2024-21762 currently ranks highest (100/100): Fortinet FortiOS Out-of-Bound Write Vulnerability.

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