CVE entry · CVE-2026-24858
CVE-2026-24858: Fortinet Multiple Products Authentication Bypass Using an Alternate Path or Channel Vulnerability
Fortinet FortiAnalyzer, FortiManager, FortiOS, and FortiProxy contain an authentication bypass using an alternate path or channel that could allow an attacker with a FortiCloud account and a registered device to log into other devices registered to other accounts, if FortiCloud SSO authentication is enabled on those devices.
- Actively exploited: added to CISA’s KEV catalog on January 27, 2026.
- Use by ransomware: not established so far.
- Remediation deadline for US federal agencies: January 30, 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 (www.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 Multiple Products Heap-based Buffer Overflow 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