Threat Intelligence / CVE / CVE-2026-24858

CVE-2026-24858 — Fortinet Fortianalyzer

CISA KEV

CVSS v3.1 9.8 (CRITICAL) · EPSS 2.2% (higher than 84.6% of all scored CVEs) · Priority 9/10 · Published 2026-01-27

As of 2026-01-29, CVE-2026-24858 is a CRITICAL-severity vulnerability in Fortinet Fortianalyzer, CVSS v3.1 9.8, EPSS 2.2% (84.6th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-01-27), with a US federal remediation deadline of 2026-01-30. Threadlinqs Intelligence links 5 tracked threat campaigns to CVE-2026-24858, most recently “Edge Infrastructure Under Siege: Tenable and SentinelOne Datasets Reveal Convergent Nation-State and Criminal Exploitation of Perimeter Devices”.

Last updated: 2026-01-29

What is 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, 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.

The record classifies CVE-2026-24858 under weakness class CWE-288. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 5 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 228 days ago.

Severity and exploitation probability

CVSS v3.1 base score: 9.8 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (FIRST): 2.2% probability of exploitation in the next 30 days, higher than 84.6% of all scored CVEs
CISA KEV: Listed since 2026-01-27, federal remediation deadline 2026-01-30
Threadlinqs priority: 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
Published: 2026-01-27, last modified 2026-01-29

Is CVE-2026-24858 being exploited?

CISA added CVE-2026-24858 to the Known Exploited Vulnerabilities catalog on 2026-01-27, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-01-30 under BOD 22-01. It currently carries a trending score of 36 in the Threadlinqs vulnerability feed.

Affected products and versions

Fortinet: Fortianalyzer, Fortimanager, Fortiproxy, Fortiweb, Fortios

How to fix CVE-2026-24858

Vendor advisory: https://fortiguard.fortinet.com/psirt/FG-IR-26-060. Because CVE-2026-24858 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-01-30. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2026-24858

5 tracked threats in the Threadlinqs corpus reference CVE-2026-24858, either in the campaign’s CVE list or as an indicator on the campaign record.

Edge Infrastructure Under Siege: Tenable and SentinelOne Datasets Reveal Convergent Nation-State and Criminal Exploitation of Perimeter Devices — HIGH · 2026-08-26
FortiBleed: Mass Credential Compromise Campaign Against Internet-Exposed Fortinet FortiGate Devices (86,644 Devices, 194 Countries) — CRITICAL · 2026-07-11
FortiBleed Credential Theft Campaign Linked to INC and Lynx Ransomware Operations — CRITICAL · 2026-07-05
FortiGate SSO Authentication Bypass Campaign (CVE-2025-59718, CVE-2025-59719, CVE-2026-24858) — CRITICAL · 2026-03-10
Fortinet FortiCloud SSO Cross-Tenant Authentication Bypass (CVE-2026-24858) — CRITICAL · 2026-01-27

Sources

Seeded from nvd and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.

Full detection coverage & IOCs for threats exploiting CVE-2026-24858 are available via the Threadlinqs MCP server (Purple tier). View plans →

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