CVE-2026-39808 - Fortinet FortiSandbox OS Command Injection Vulnerability

Technical Severity

CVSS v3.1 Metrics

CRITICAL

9.8 / 10

Minimal Risk Critical

Vector Specification

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation Likelihood

EPSS Prediction

92.82 %

Predictive Probability

Percentile Rank

99.8 th

Documented as more likely to be exploited than 99.8% of known CVEs.

Detection Date

Jul 16, 2026

Remediation Due

Jul 19, 2026

CISA Catalog Active

Threat Analysis

Fortinet FortiSandbox contains an OS command injection vulnerability that could allow an unauthenticated attacker to execute unauthorized code or commands via crafted HTTP requests.

Remediation Directive

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.

External Intelligence

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

CISA

CISA Advisory

https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk

CISA

CISA Advisory

https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk

NVD

National Vulnerability Database

https://nvd.nist.gov/vuln/detail/CVE-2026-39808