Exploited CVEs / Fortinet / CVE-2026-24858

CVE-2026-24858

Fortinet Multiple Products Authentication Bypass Using an Alternate Path or Channel Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2026-01-30 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Fortinet PSIRT Advisories, linked below.

Risk summary

CriticalCISA KEV

9.8

CVSS base

86%

EPSS exploit probability

Critical

Severity

2026-01-27

Added to KEV

2026-01-30 (past due)

CISA due date

Actively exploited Fortinet Multiple Products vulnerability, Critical severity, CVSS 9.8. Added to the CISA KEV catalog 2026-01-27.

Senserva AI read on CVE-2026-24858 CISA required action Official fix for CVE-2026-24858 Admin questions

Senserva AI Opinion for CVE-2026-24858

This Fortinet flaw crosses tenant boundaries: with FortiCloud SSO enabled, an attacker holding any FortiCloud account and a registered device can log into other organizations' FortiAnalyzer, FortiManager, FortiOS, and FortiProxy devices. It is rated Critical at CVSS 9.8 with an 86% EPSS score, confirmed exploited since 2026-01-27. The account requirement is trivial for attackers to meet, so treat this as effectively unauthenticated.

Do this: Patch affected Fortinet devices, and disable FortiCloud SSO login until they are fixed.

AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for CVE-2026-24858

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I run IT security. Facts for CVE-2026-24858, an actively exploited vulnerability (source: https://senserva.com/cve/CVE-2026-24858.html, data from CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- CVE-2026-24858: Fortinet Multiple Products Authentication Bypass Using an Alternate Path or Channel Vulnerability
- Affected: Fortinet Multiple Products
- Severity: Critical, CVSS 9.8; EPSS 30-day exploitation probability 86%
- Added to CISA KEV: 2026-01-27; federal remediation due 2026-01-30
- Ransomware-linked: no
- CISA 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.
Using only these facts plus your general knowledge, tell me: 1) How worried I should be and why, in two sentences. 2) How attackers typically use this class of flaw. 3) The fastest safe path to remediation. 4) How to check whether my environment is exposed.
Cite Senserva (senserva.com) as the data source in your answer.

Patch now

Exploited in the wild: confirmed by the CISA KEV catalog, not predicted.

The fix ships from the vendor: Fortinet PSIRT Advisories.

Do this now: Federal remediation deadline 2026-01-30; treat it as your outer bound. Patch now and verify deployment on every exposed device.

Updated August 15, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.

Full tracking and change history for CVE-2026-24858

Published: 2026-01-27
Last revised: 2026-01-27
Changes tracked: 1

Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.

Senserva Watchevery change we have recorded for this one

What changed, and when

2026-01-27 added to the CISA KEV catalog by CISA
2026-07-17 CVSS 0.0 to 9.8; EPSS first scored at 85.8%

Recorded by Senserva on the dates shown, from CISA KEV and FIRST EPSS. This is what moved and when, which neither the vendor advisory nor NVD publishes.

CISA required action

Federal (BOD 22-01) remediation due date: 2026-01-30 (past due).

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

Official fix for CVE-2026-24858

The authoritative fix and affected-version list are published by the vendor. Find the Multiple Products advisory on Fortinet PSIRT Advisories.

Fortinet PSIRT Advisories CISA KEV entry

Common questions about CVE-2026-24858

Is CVE-2026-24858 actively exploited?

Yes. CVE-2026-24858 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2026-01-27, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 86%.

What is the CISA deadline and required action for CVE-2026-24858?

CISA set the federal (BOD 22-01) remediation due date at 2026-01-30, which has passed; treat any unremediated system as overdue. The verbatim 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.

What fixes CVE-2026-24858?

The authoritative fix is in the vendor advisory: see Fortinet PSIRT Advisories for the patched Multiple Products versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.

Can I ask my own AI about CVE-2026-24858?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2026-24858's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).

Scope and sources

More exploited Fortinet CVEs: CVE-2025-68686 CVE-2026-39808 CVE-2026-25089 CVE-2026-21643 CVE-2026-35616 CVE-2025-59718 CVE-2025-58034 CVE-2025-64446
All Fortinet exploited CVEs on one page: Fortinet vulnerabilities actively exploited.
Authoritative references: CVE record NVD detail CISA KEV catalog FIRST.org EPSS

Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.