What is CVE-2026-39808?

CVE-2026-39808 is a critical-severity vulnerability in Fortinet Fortisandbox, classified under OS Command Injection. CVSS score: 9.1/10. Published 2026-04-14.

How severe is CVE-2026-39808?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Is CVE-2026-39808 known to be exploited?

3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

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: 0.279 (96.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C.

Affected products

Fortinet Fortisandbox — versions 4.4.0
Fortinet Fortisandbox Paas — versions 23.4.4374, 23.4.4350, 23.3.4329

Weakness classification (CWE)

CWE-78 — OS Command Injection

Public proof-of-concept exploits

References

https://fortiguard.fortinet.com/psirt/FG-IR-26-100

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: 9.1/10. Published 2026-04-14.
How severe is CVE-2026-39808?: Critical severity. CVSS v3 base score is 9.1 out of 10.
Is CVE-2026-39808 known to be exploited?: 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.