CVE-2026-39808
CriticalExploitedPublic exploitA 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
Published Apr 16, 2026 · Updated Jul 17, 2026 · Also known as TR-26-0107
Key Facts
Patch immediately- CVE-2026-39808 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Fortisandbox (Fortinet), Fortisandboxpaas (Fortinet).
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jun 9, 2026. Public exploit code is available.
- EPSS estimates a 47% probability of exploitation in the next 30 days.
- Fixed versions are available, including Fortisandbox 4.4.9.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
47%
Higher than 98.8% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2026-39808 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
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
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Jul 16, 2026 | Jul 19, 2026 | Not reported |
| Industry KEV feed | Jun 9, 2026 | Jul 19, 2026 | Not reported |
| CIRCL KEV | Jun 12, 2026 | Jul 19, 2026 | Not reported |
| ENISA EUVD | Jul 16, 2026 | n/a | Not reported |
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.
Affected Products
19 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| FortisandboxFortinet | 4.4.0, 4.4.1, 4.4.2, 4.4.3, 4.4.4, 4.4.5, 4.4.6, 4.4.7 | 4.4.9 |
| FortisandboxpaasFortinet | 21.3.4055, 21.4.4072, 22.1.4113, 22.2.4134, 22.2.4151, 23.1.4245, 23.3.4329, 23.4.4350 | n/a |
Patched Releases
Fortisandbox
4.4.9
Timeline
Publicly disclosed
Apr 16, 2026
Added to Industry KEV feed
Jun 9, 2026
Added to CIRCL KEV
Jun 12, 2026
Added to CISA KEV
Jul 16, 2026
Added to ENISA EUVD
Jul 16, 2026
Last updated
Jul 17, 2026
Weakness Type
- CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
References
- advisoryhttps://fortiguard.fortinet.com/psirt/FG-IR-26-100
- advisoryhttps://fortiguard.fortinet.com/psirt/FG-IR-26-112
- advisoryUSOM advisory
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
FAQ
Common Questions.
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
Affected: Fortisandbox (Fortinet) versions 4.4.0, 4.4.1, 4.4.2, 4.4.3, 4.4.4, 4.4.5, 4.4.6, 4.4.7; Fortisandboxpaas (Fortinet) versions 21.3.4055, 21.4.4072, 22.1.4113, 22.2.4134, 22.2.4151, 23.1.4245, 23.3.4329, 23.4.4350. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jun 9, 2026.
Yes. It was added on Jul 16, 2026 with a federal remediation due date of Jul 19, 2026.
Public exploit code is available.
Fixed versions are available, including Fortisandbox 4.4.9.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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