Overview
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.
Please adhere to Fortinet's guidelines to assess exposure and mitigate risks. Check for signs of potential compromise on all internet accessible Fortinet products affected by this vulnerability. Apply any final mitigations provided by the vendor as soon as they become available. For more information please see: https://fortiguard.fortinet.com/psirt/FG-IR-26-060 ; https://www.fortinet.com/blog/psirt-blogs/analysis-of-sso-abuse-on-fortios ; https://nvd.nist.gov/vuln/detail/CVE-2026-24858
Key Details
| Property | Value |
|---|
| CVE ID |
CVE-2026-24858 |
| Vendor / Product |
Fortinet — Multiple Products |
| NVD Published | 2026-01-27 |
| NVD Last Modified | 2026-01-29 |
| CVSS 3.1 Score | 9.8 |
| CVSS 3.1 Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| Severity | CRITICAL |
| CWE |
CWE-288
|
| CISA KEV Added | 2026-01-27 |
| CISA KEV Deadline | 2026-01-30 |
| Known Ransomware Use |
No |
Required Action
CISA BOD 22-01 Deadline: 2026-01-30.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Timeline
| Date | Event |
|---|
| 2026-01-27 | Added to CISA Known Exploited Vulnerabilities catalog |
| 2026-01-30 | CISA BOD 22-01 remediation deadline |