CVE entry · CVE-2025-25249
CVE-2025-25249: Fortinet Multiple Products Heap-based Buffer Overflow Vulnerability
Fortinet FortiOS, FortiSwitchManager, and FortiSASE contain a heap-based buffer overflow vulnerability that allows an attacker to execute unauthorized code or commands via specially crafted packets.
- Actively exploited: added to CISA’s KEV catalog on September 9, 2026.
- Use by ransomware: not established so far.
- Remediation deadline for US federal agencies: September 12, 2026.
Description from CISA’s KEV catalog.
What to do
- Check whether your estate includes affected Fortinet products, including internet-facing devices.
- Apply the vendor’s patch or mitigations (references below). Failing that, isolate the product or stop using it, as CISA requires of US federal agencies.
- An exploited vulnerability has often been used before it was fixed: look for signs of compromise, especially on internet-facing devices.
References
- Vendor advisory or reference cited by CISA (fortiguard.fortinet.com)
- NVD entry (NIST)
- CISA KEV catalog
Other Fortinet vulnerabilities
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Fortinet Multiple Products Path Traversal Vulnerability
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Fortinet FortiMail Path Traversal Vulnerability
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Fortinet FortiOS Exposure of Sensitive Information to an Unauthorized Actor Vulnerability
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Fortinet FortiSandbox OS Command Injection Vulnerability
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Fortinet FortiSandbox OS Command Injection Vulnerability
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Fortinet FortiClient EMS SQL Injection Vulnerability