Is itCheck something

No. CVE-2026-104286

Attackers can plant files on Fortinet FortiMail servers

Being used now

Yes. Attackers are using this right now.

Organizations using Fortinet FortiMail for email security.

What to do

Apply Fortinet's update for FortiMail.

Confirmed in attacksOct 1, 2026
ProductFortinet FortiMail
GitHub repos5
Attack likelihood, next 30 days4.6%

Attack likelihood is EPSS, a daily estimate from FIRST.org of how likely this bug is to be used in attacks in the next 30 days.

The official 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.

For your tech helper or AI assistant

A read-only checklist. Paste it into Claude, ChatGPT or a coding agent; it only looks and changes nothing.

Read-only check, change nothing, send nothing anywhere.
Is Fortinet FortiMail (CVE-2026-104286) installed or running on this machine or in this project?
1. Find every copy and its version (apps, packages, containers, lockfiles).
2. Compare each version against the vendor's fixed version for CVE-2026-104286. Quote the vendor page you used.
3. Report a table: where, version, fixed version, status (exposed / fixed / not installed / unsure).
4. List the exact update steps, but do not run them.
Download playbook (.md)

Code on GitHub

Repos named after this bug. Some are scanners or write-ups, some are working attack code. Do not run them on a machine you care about.

Sources