Exploited vulnerability · CISA KEV

Is CVE-2026-24858 exploited? Yes: in CISA KEV since 27 Jan 2026

Gociux · Fortinet Multiple Products · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2026-24858, Fortinet Multiple Products Authentication Bypass Using an Alternate Path or Channel Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 27 Jan 2026, the day it was published. It affects Fortinet Multiple Products, an internet-facing product of the kind attackers use for initial access. If you run it, CISA's required action is: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

What it is

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.

What to do

1. Check whether you run it. Look for Multiple Products in your asset inventory, including appliances and cloud images. Stack check lists every exploited Fortinet CVE at once.
2. Apply the fix. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
3. If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 27 Jan 2026.
4. Get told next time. Email alerts when CISA adds a CVE for Fortinet.

Other exploited CVEs in Multiple Products

• CVE-2025-61624: Fortinet Multiple Products Path Traversal Vulnerability (16 Oct 2026)
• CVE-2025-25249: Fortinet Multiple Products Heap-based Buffer Overflow Vulnerability (9 Sep 2026)
• CVE-2025-59718: Fortinet Multiple Products Improper Verification of Cryptographic Signature Vulnerability (16 Dec 2025)
• CVE-2025-32756: Fortinet Multiple Products Stack-Based Buffer Overflow Vulnerability (14 May 2025)
• CVE-2024-23113: Fortinet Multiple Products Format String Vulnerability (9 Oct 2024)
• CVE-2022-40684: Fortinet Multiple Products Authentication Bypass Vulnerability (11 Oct 2022)

References

• www.fortinet.com/blog/psirt-blogs/analysis-of-sso-abuse-on-fortios
• nvd.nist.gov/vuln/detail/CVE-2026-24858

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in January 2026 · Fortinet scorecard · act-now radar.