CVE-2026-104286

Fortinet FortiMail: Path Traversal

As of , CVE-2026-104286 in Fortinet FortiMail is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch now.

Exploited
Yes: CISA listed it on 1 October 2026
US federal deadline
4 October 20263 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Not known to CISA
Forensic triage
Required by CISA under BOD 26-04Agencies must also look for signs that attackers already got in.
EPSS score
0.02Higher than 81% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
Public exploit
None foundNeither Metasploit nor Exploit-DB lists one.
Fix
Vendor advice: fortiguard.fortinet.comLinks below, from CISA's entry.

What CISA says to do

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's required action

What the flaw is

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.

CISA's description

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.

The CVE record's description, from fortinet

CVE published
1 October 2026
Assigned by
fortinet
CVSS
9.8 Critical (CVSS 3.1, from the CNA)
CWE-22
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-158
Improper Neutralization of Null Byte or NUL Character
CISA SSVC, exploitation
active
CISA SSVC, automatable
yes
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.

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