MajorExploited now Active exploitation

CVE-2026-104286: Fortinet FortiMail Path Traversal Vulnerability

CISA KEV · officialPublished Oct 1, 2026Risk 77/100

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. Vendor: Fortinet — FortiMail 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. Due: 2026-10-04

Recommended 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 remediation due: 2026-10-04

Technical details

Vendor: Fortinet
Product: FortiMail
Exploitation: active
Evidence: official

Evidence and sources

This record is attributed to CISA KEV. Exploitation status and remediation guidance are kept separate from the vulnerability's technical severity.

Open primary source