Critical severity · published Jan 27, 2026
CVE-2026-24858
Fortinet Multiple Products Authentication Bypass Using an Alternate Path or Channel Vulnerability
In wildKEV
9.8
CVSS
86.6%
EPSS
Yes
On KEV
Description
An Authentication Bypass Using an Alternate Path or Channel vulnerability [CWE-288] vulnerability in Fortinet FortiAnalyzer 7.6.0 through 7.6.5, FortiAnalyzer 7.4.0 through 7.4.9, FortiAnalyzer 7.2.0 through 7.2.11, FortiAnalyzer 7.0.0 through 7.0.15, FortiManager 7.6.0 through 7.6.5, FortiManager 7.4.0 through 7.4.9, FortiManager 7.2.0 through 7.2.11, FortiManager 7.0.0 through 7.0.15, FortiNAC-F 7.6.3 through 7.6.5, FortiOS 7.6.0 through 7.6.5, FortiOS 7.4.0 through 7.4.10, FortiOS 7.2.0 through 7.2.12, FortiOS 7.0.0 through 7.0.18, FortiProxy 7.6.0 through 7.6.4, FortiProxy 7.4.0 through 7.4.12, FortiProxy 7.2.0 through 7.2.15, FortiProxy 7.0.0 through 7.0.22, FortiWeb 8.0.0 through 8.0.3, FortiWeb 7.6.0 through 7.6.6, FortiWeb 7.4.0 through 7.4.11 may 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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)86.6% · higher than 100% of CVEs
Exploited in the wildYes
CISA KEVListed Jan 27, 2026
Federal remediation dueJan 30, 2026
Ransomware campaign useNot known
Affected products
Which versions
FO
FortiManager · Fortinet
7.6.0 through 7.6.5; 7.4.0 through 7.4.9; 7.2.0 through 7.2.11; 7.0.0 through 7.0.15 · source: vendor, NVD
FO
FortiOS · Fortinet
7.6.0 through 7.6.5; 7.4.0 through 7.4.10; 7.2.0 through 7.2.12; 7.0.0 through 7.0.18 · source: vendor, NVD
FO
FortiAnalyzer · Fortinet
7.6.0 through 7.6.5; 7.4.0 through 7.4.9; 7.2.0 through 7.2.11; 7.0.0 through 7.0.15 · source: vendor, NVD
FO
FortiNAC-F · Fortinet
7.6.3 through 7.6.5 · source: vendor, NVD
FO
FortiProxy · Fortinet
7.6.0 through 7.6.4; 7.4.0 through 7.4.12; 7.2.0 through 7.2.15; 7.0.0 through 7.0.22 · source: vendor, NVD
FO
FortiWeb · Fortinet
8.0.0 through 8.0.3; 7.6.0 through 7.6.6; 7.4.0 through 7.4.11 · source: vendor, NVD
RA
Ruggedcom Ape1808 Firmware · Siemens
All versions, or not specified · source: NVD
RA
MP
Multiple Products · Fortinet
All versions, or not specified · source: KEV
In the news
VulnerabilityCritical
Siemens RUGGEDCOM APE1808 Devices
View CSAF Summary Fortinet has published information on vulnerabilities in FORTIOS. This advisory lists the related Siemens Industrial products. Siemens has released a new version for RUGGEDCOM APE1808 and recommends to update to the latest version. The following versions of Siemens RUGGEDCOM APE1808 Devices are affected: RUGGEDCOM APE1808 vers:all/*, vers:all/* (CVE-2026-24858, CVE-2025-55018, CVE-2025-62439, CVE-2025-64157) CVSS Vendor Equipment Vulnerabilities v3 9.8 Siemens Siemens RUGGEDCOM APE1808 Devices Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling'), Improper Verification of Source of a Communication Channel, Use of Externally-Controlled Format String, Authentication Bypass Using an Alternate Path or Channel Background Critical Infrastructure Sectors: Critical Manufacturing, Energy, Transportation Systems Countries/Areas Deployed: Worldwide Company Headquarters Location: Germany Vulnerabilities Expand All + CVE-2025-55018 An inconsistent interpretation of http requests ('http request smuggling') vulnerability in Fortinet FortiOS 7.6.0, FortiOS 7.4.0 through 7.4.9, FortiOS 7.2 all versions, FortiOS 7.0 all versions, FortiOS 6.4.3 through 6.4.16 may allow an unauthenticated attacker to smuggle an unlogged http request through the firewall policies via a specially crafted header View CVE Details Affected Products Siemens RUGGEDCOM APE1...
Mar 12, 2026·CISA Advisories
VulnerabilityHigh
[CISA KEV] CVE-2026-24858: Fortinet Multiple Products - 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.
MPMultiple ProductsCVE-2026-24858
Jan 27, 2026·CISA KEV
Affected product
FO
FortiManager
Fortinet
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