Cyber Posture

CVE-2026-39808

Critical

Published: 14 April 2026

Published
14 April 2026
Modified
22 April 2026
KEV Added
Patch
CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.1310 94.1th percentile
Risk Priority 27 60% EPSS · 20% KEV · 20% CVSS

Description

Adversaries may abuse Unix shell commands and scripts for execution.

Security Summary

CVE-2026-39808 is an OS command injection vulnerability (CWE-78) affecting Fortinet FortiSandbox versions 4.4.0 through 4.4.8. The issue arises from improper neutralization of special elements used in an OS command, which may allow an attacker to execute unauthorized code or commands via an unspecified attack vector. Published on 2026-04-14, it carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), marking it as critical due to its potential for severe impact.

An unauthenticated attacker with network access can exploit this vulnerability with low attack complexity and no user interaction required. Exploitation enables arbitrary OS command execution, granting high levels of control over confidentiality, integrity, and availability, potentially leading to complete system compromise.

Fortinet's advisory at https://fortiguard.fortinet.com/psirt/FG-IR-26-100 provides details on the vulnerability. A related GitHub repository at https://github.com/samu-delucas/CVE-2026-39808 is also referenced, offering additional resources for practitioners seeking mitigation or patch information.

Details

CWE(s)
CWE-78

Affected Products

fortinet
fortisandbox
4.4.0 — 4.4.9

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1059.004 Unix Shell Execution
Adversaries may abuse Unix shell commands and scripts for execution.
Why these techniques?

Unauthenticated remote OS command injection in public-facing FortiSandbox enables exploitation of public-facing application (T1190) and arbitrary Unix shell command execution (T1059.004).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

References