CVE-2026-104286

CRITICALCVSS 9.8Known Exploited

CISA Known Exploited Vulnerability

https://fortiguard.fortinet.com/psirt/FG-IR-26-175 ; ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-104286

Remediation deadline: October 4, 2026

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.

Timeline

Published:October 1st, 2026 8:17 PM

Last modified:October 7th, 2026 6:17 PM

Added to KEV:October 1st, 2026

CVSS Scoring

CVSS v3: 9.8 (CRITICAL)

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Software

From NVD CPE configuration data

Vendors

fortinet

Products

fortimail

Weaknesses (CWE)

CWE-22

References & Reports

Advisories, patches, and third-party reports

Source: NIST NVD · Data may lag official sources by up to one minute