CVE-2026-24858 - Fortinet Multiple Products Authentication Bypass Using an Alternate Path or Channel Vulnerability

Technical Severity

CVSS v3.1 Metrics

CRITICAL

9.8 / 10

Minimal Risk Critical

Vector Specification

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation Likelihood

EPSS Prediction

3.41 %

Predictive Probability

Percentile Rank

87.1 th

Documented as more likely to be exploited than 87.1% of known CVEs.

Detection Date

Jan 27, 2026

Remediation Due

Jan 30, 2026

CISA Catalog Active

Threat Analysis

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.

Remediation Directive

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Asset Context

Vendor Identity

Fortinet

Affected Product

Multiple Products

Ransomware Status

Campaign Use Unknown

Weakness Classification

CWE-288

External Intelligence

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

NVD

National Vulnerability Database

https://nvd.nist.gov/vuln/detail/CVE-2026-24858