RCE in Fortinet Fortisandbox
CVE-2026-39808
A improper neutralization of special elements used in an os command ('os command injection') vulnerability in Fortinet FortiSandbox 4.4.0 through 4.4.8 may allow attacker to execute unauthorized code or commands via <insert attack vector h…
Vulnerability class: Command Injection (OS Command Injection)
EPSS: 0.842 (99.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Fortinet Fortisandbox — versions 4.4.0
- Fortinet Fortisandbox Paas — versions 23.4.4374, 23.4.4350, 23.3.4329
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
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.
Public proof-of-concept exploits
References
- psirt@fortinet.com (Vendor Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Exploit, Third Party Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)
Frequently asked questions
- What is CVE-2026-39808?
- CVE-2026-39808 is a critical-severity vulnerability in Fortinet Fortisandbox, classified under OS Command Injection. CVSS score: 9.8/10. Published 2026-04-14.
- How severe is CVE-2026-39808?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2026-39808 known to be exploited?
- Yes. CVE-2026-39808 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-07-16), indicating it is being actively exploited. 5 public proof-of-concept repositories are indexed.