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 2026-10-04; treat it as your outer bound. Patch now and verify deployment on every exposed device.

Updated October 1, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.

Exploited CVEs / Fortinet / CVE-2026-104286

CVE-2026-104286

Fortinet FortiMail Path Traversal Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2026-10-04; 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

In the top 10 of the Senserva CVE Ranking (as of 2026-10-03)
CriticalCISA KEV
9.8
CVSS v3 base
2.2%
EPSS exploit probability
Critical
Severity
2026-10-01
Added to KEV
2026-10-04
CISA due date

Actively exploited Fortinet FortiMail vulnerability, Critical severity, CVSS v3 9.8. Added to the CISA KEV catalog 2026-10-01.

CISA required actionOfficial fix for CVE-2026-104286What the press saysAdmin questions#9 hottest CVE right now
Senserva AI Opinion and rich prompt for CVE-2026-104286

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

Full tracking and change history for CVE-2026-104286

Published
2026-10-01
Last revised
2026-10-01
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

CISA confirmed active exploitation of CVE-2026-104286 on 2026-10-01.

  • 2026-10-01 added to the CISA KEV catalog by CISA
  • 2026-10-03 CVSS 0.0 to 9.8; EPSS first scored at 2.2%

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.

What the press says about CVE-2026-104286

Trusted-source coverage, pulled live from their own feeds.

“Exploited Fortinet FortiMail Zero-Day Calls for Urgent Action” SecurityWeek, 2026-10-02
“Critical FortiMail zero-day exploited in the wild (CVE-2026-104286)” Help Net Security, 2026-10-02
“Fortinet warns of critical FortiMail flaw exploited in zero-day attacks” BleepingComputer, 2026-10-01

CISA required action

Federal remediation due date: 2026-10-04.

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Official fix for CVE-2026-104286

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

Fortinet PSIRT AdvisoriesCISA KEV entry

Common questions about CVE-2026-104286

Is CVE-2026-104286 actively exploited?

Yes. CVE-2026-104286 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2026-10-01, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 2.2%.

What is the CISA deadline and required action for CVE-2026-104286?

CISA set the federal remediation due date at 2026-10-04. The verbatim required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

What fixes CVE-2026-104286?

The authoritative fix is in the vendor advisory: see Fortinet PSIRT Advisories for the patched FortiMail 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-2026-104286?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2026-104286'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 (morning and afternoon US Central).

Scope and sources

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CVE-2025-25249CVE-2025-68686CVE-2026-25089CVE-2026-39808CVE-2026-21643CVE-2026-35616CVE-2026-24858CVE-2025-59718

All Fortinet exploited CVEs on one page: Fortinet vulnerabilities actively exploited.

Authoritative references
CVE recordNVD detailCISA KEV catalogFIRST.org EPSS

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

New to a term on this page? CVE, KB, KEV, CVSS, and EPSS are each explained once, on the Senserva security lexicon. Reference: Microsoft CVE and vulnerability management and the Microsoft patching guide.
All information provided as is, without warranty; verify against the vendor advisory before acting. All information and usage is subject to the Senserva EULA. Data notice and terms.