What is CVE-2026-24858?

CVE-2026-24858 is a critical-severity vulnerability in Fortinet Fortianalyzer, classified under Authentication Bypass Using an Alternate Path or Channel. CVSS score: 9.8/10. Published 2026-01-27.

How severe is CVE-2026-24858?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2026-24858 known to be exploited?

Yes. CVE-2026-24858 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-01-27), indicating it is being actively exploited. 5 public proof-of-concept repositories are indexed.

Vulnerability in Fortinet Fortianalyzer

CVE-2026-24858

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.

EPSS: 0.861 (99.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Fortinet Fortianalyzer — versions 7.6.0, 7.4.0, 7.2.0
Fortinet Fortimanager — versions 7.6.0, 7.4.0, 7.2.0
Fortinet Fortinac-f — versions 7.6.3
Fortinet Fortios — versions 7.6.0, 7.4.0, 7.2.0
Fortinet Fortiproxy — versions 7.6.0, 7.4.0, 7.2.0
Fortinet Fortiweb — versions 8.0.0, 7.6.0, 7.4.0
Siemens Ruggedcom_ape1808
Siemens Ruggedcom_ape1808_firmware

Weakness classification (CWE)

CWE-288 — Authentication Bypass Using an Alternate Path or Channel

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2026-01-27. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2026-01-30.

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

Public proof-of-concept exploits

References

psirt@fortinet.com (Vendor Advisory)
0b142b55-0307-4c5a-b3c9-f314f3fb7c5e (Third Party Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (Mitigation, Vendor Advisory)

Frequently asked questions

What is CVE-2026-24858?: CVE-2026-24858 is a critical-severity vulnerability in Fortinet Fortianalyzer, classified under Authentication Bypass Using an Alternate Path or Channel. CVSS score: 9.8/10. Published 2026-01-27.
How severe is CVE-2026-24858?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2026-24858 known to be exploited?: Yes. CVE-2026-24858 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-01-27), indicating it is being actively exploited. 5 public proof-of-concept repositories are indexed.