CVE-2025-59718 Fortinet Multiple Products: security feature bypass
In plain words: A built-in safety check — like a warning before opening a downloaded file — can be skipped. Makes other attacks, like malicious downloads, work without the usual warning.
Confirmed exploited by CISA on · US federal patch deadline Dec 23, 2025
What to do
- Install Fortinet's security update for Multiple Products. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Patch edge devices first — attackers often start scanning for them within hours of a fix.
- Never expose the device's admin page to the internet.
- After patching a device that was exposed, follow the vendor's compromise checks, end active sessions and change passwords.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: They face the internet and guard the whole network, so a flaw here can hand attackers a way in — and these devices usually run no antivirus, so break-ins go unnoticed.
The details
- Official name
- Fortinet Multiple Products Improper Verification of Cryptographic Signature Vulnerability
- Product
- Fortinet Multiple Products
- CISA description
- Fortinet FortiOS, FortiSwitchMaster, FortiProxy, and FortiWeb contain an improper verification of cryptographic signature vulnerability that may allow an unauthenticated attacker to bypass the FortiCloud SSO login authentication via a crafted SAML message. Please be aware that CVE-2025-59719 pertains to the same problem and is mentioned in the same vendor advisory. Ensure to apply all patches mentioned in the advisory.
- Type of flaw
- Security feature bypass (CWE-347)
- Confirmed exploited
- Dec 16, 2025
- US federal patch deadline
- Dec 23, 2025
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Answering about CVE-2025-59718 ·
Questions about CVE-2025-59718
Is CVE-2025-59718 being exploited?
Yes. CISA added CVE-2025-59718 to its Known Exploited Vulnerabilities catalog on Dec 16, 2025, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2025-59718?
Install Fortinet's security update for Multiple Products. If no update exists, follow the vendor's workaround or stop using the product until one ships. Patch edge devices first — attackers often start scanning for them within hours of a fix.
Am I affected by CVE-2025-59718?
Only if you use Fortinet Multiple Products. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.