CVEs / CVE-2026-104286
CVE-2026-104286: Fortinet FortiMail Path Traversal Vulnerability
- Known exploited in the CISA KEV catalog since 1 Oct 2026
- critical 9.8 CVSS 3.1 (from the CNA)
- EPSS 4.57% chance of exploitation in the next 30 days, higher than 91% of CVEs (30 Oct 2026)
- Last changed at its sources
Are you affected? Check your servers with Stackurity: it lists the software on each server and the vulnerabilities to fix first.
Check your servers with Stackurity Already using Stackurity? Search for CVE-2026-104286
Summary
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.
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, FortiMail 7.0 all versions may allow an unauthenticated attacker to write arbitrary files on the underlying system via crafted HTTP or HTTPS requests.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Fortinet FortiMail | from 8.0.0, up to and including 8.0.1 | — |
| Fortinet FortiMail | from 7.6.0, up to and including 7.6.6 | — |
| Fortinet FortiMail | from 7.4.0, up to and including 7.4.8 | — |
| Fortinet FortiMail | from 7.2.0, up to and including 7.2.9 | — |
| Fortinet FortiMail | from 7.0.0, up to and including 7.0.9 | — |
Exploitation
| In CISA KEV since | 1 Oct 2026 |
|---|---|
| Due date for US federal agencies | 4 Oct 2026 |
| Used in ransomware campaigns | Unknown |
| 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. |
Severity
| CVSS 3.1 | 9.8 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HScored by the CNA ([email protected]) |
|---|---|
| Weakness | CWE-22 |
References
- CVE-2026-104286 on NVD
- CVE-2026-104286 in the CISA KEV catalog
- https://fortiguard.fortinet.com/psirt/FG-IR-26-175 (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk (cited by CISA)
- https://fortiguard.fortinet.com/psirt/FG-IR-26-175 Mitigation, Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-104286 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.