CVE-2026-104286

Fortinet FortiMail Path Traversal Vulnerability

Fortinet FortiMailNetwork & edge

CVSS

9.8Critical

ExploitationExploited in the wildAdded to KEV 1 Oct 2026CISA KEV

Exploit odds (EPSS)2.20%Chance of exploitation activity in the next 30 days, higher than 82% of CVEs. Scored 23 Oct 2026FIRST EPSS

Fixed inNone listedNo source names a fixed version. Check the vendor advisory below

Federal deadline4 Oct 2026Remediation due date for US federal agenciesCISA KEV

CISA required actionApply 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 KEV

Patching is not enoughCISA requires federal agencies to look for signs of compromise on affected systems, not only patch (forensic triage under BOD 26-04). Treat exposed systems as possibly compromised. CISA guidance

What fixes it

No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.

Timeline

1 Oct 2026Added to CISA KEVCISA KEV
1 Oct 2026, 19:17 UTCPublishedCVE List
23 Oct 2026, 23:43 UTCExploit code publicGitHub proof-of-concept repositories

Reports 1

1 outlet mention it. Reports are not confirmation; each links to its source.

CompleteTech-LLC/fortimail-cve-2026-104286-check: Standalone defensive checker project for CVE-2026-104286: Fortinet FortiMail: Path traversal / NULL-byte arbitrary file write. One exploit per repository; implementation pending.GitHub proof-of-concept repositories, 23 Oct 2026Exploit code

Description

Fortinet FortiMail contains a path traversal and an improper neutralization of NULL byte or NULL character vulnerability that may allow an unauthenticated attacker to write arbitrary files on the underlying system via crafted HTTP or HTTPS requests.

Text from CVE List

Affected versions 5

FortiMailaffected: 8.0.0CVE List
FortiMailaffected: 7.6.0 through 7.6.5CVE List
FortiMailaffected: 7.4.0 through 7.4.6CVE List
FortiMailaffected: 7.2.0 through 7.2.9CVE List
FortiMailaffected: 7.0.0 through 7.0.9CVE List