---
title: "CVE-2026-104286: Fortinet FortiMail Path Traversal Vulnerability"
url: https://erroneo.us/security/cve/CVE-2026-104286/
description: "CVE-2026-104286 (Fortinet FortiMail): Exploited in the wild (CISA KEV). An improper limitation of a pathname to a restricted directory ('path traversal')…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-10-01
date_modified: 2026-10-07
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-104286"
kev: true
cvss: 9.8
epss: 0.02201
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-104286: Fortinet FortiMail Path Traversal Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Fortinet FortiMail. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-10-01, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-10-04 ; treat that as the outer limit, not the target.
- EPSS 2.2% , percentile 82: FIRST’s model estimates a 2.2% chance of exploitation activity in the next 30 days, higher than 82% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Act now. FortiMail CVE-2026-104286: Exploited Pre-Auth File Write — If you run a self-managed FortiMail, upgrade today and check Fortinet's indicators; this is an unauthenticated file-write zero-day on an internet-facing mail gateway.

## What it is

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.

## Affected products (CVE record)

- Fortinet FortiMail: 8.0.0, 7.6.0 <= 7.6.5, 7.4.0 <= 7.4.6, 7.2.0 <= 7.2.9, 7.0.0 <= 7.0.9

## Severity

- fortinet CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C`

## Exploitation

- CISA KEV: added 2026-10-01; federal due date 2026-10-04. Known ransomware use: Unknown.
- CISA 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.
- CISA SSVC assessment: exploitation active , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 2.20% probability of exploitation activity in the next 30 days; percentile 82.

## Sources

- [Listed in CISA KEV notes (fortiguard.fortinet.com)](https://fortiguard.fortinet.com/psirt/FG-IR-26-175)
- [CVE.org record CVE-2026-104286](https://www.cve.org/CVERecord?id=CVE-2026-104286)
- [NVD entry CVE-2026-104286](https://nvd.nist.gov/vuln/detail/CVE-2026-104286)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-104286)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk)

---
Source page: https://erroneo.us/security/cve/CVE-2026-104286/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt