CVE intelligenceCISA KEV

CVE-2026-104286

Fortinet FortiMail Path Traversal Vulnerability

Published Oct 1, 2026Sources checked Oct 3, 2026

9.8CRITICALCVSS out of 10

What this means

Actively exploited

CISA lists CVE-2026-104286 in its Known Exploited Vulnerabilities catalog, which means exploitation has been observed. The entry applies to Fortinet FortiMail.

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.

Public exploit: Not collected. Review the linked vendor advisory and apply the mitigation or fixed release for your affected product.

Fortinet PSIRT Advisories: Exploitation reported by Fortinet PSIRT Advisories (2026-10-01)

CISA KEVListedObserved exploitation

EPSS1.8%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors1Source-linked actor relationships

Overview

What is CVE-2026-104286?

An improper limitation of a pathname to a restricted directory ('path traversal') vulnerability in Fortinet FortiMail 8.0.0 through 8.0.1, FortiMail 7.6.0 through 7.6.6, FortiMail 7.4.0 through 7.4.8, FortiMail 7.2.0 through 7.2.9 may allow an unauthenticated attacker to write arbitrary files on the underlying system via crafted HTTP or HTTPS requests.