CVE-2026-39808: Fortinet FortiSandbox OS Command Injection Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 93 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 93.2%
EPSS score, percentile 99.8 of all scored records
- How severe?
- 9.1 Critical
CVSS v3.1 base score, given by the CNA
- What should I do?
CISA deadline . Apply mitigations in accordance with vendor instructions … Full text
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- 4.4.0 through 4.4.8
- 23.4.4374
- 23.4.4350
- 23.3.4329
- 23.1.4245
- 22.2.4151
and 4 more in the table below
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
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.
CISA due date for this action: .
Solution (from the CVE record)
Upgrade to FortiSandbox version 4.4.9 or above Upgrade to FortiSandbox PaaS version 5.0.2 or above
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
- https://fortiguard.fortinet.com/psirt/FG-IR-26-100
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://nvd.nist.gov/vuln/detail/CVE-2026-39808
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | 4.4.0 through 4.4.8 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | 23.4.4374 |
| Affected | 23.4.4350 |
| Affected | 23.3.4329 |
| Affected | 23.1.4245 |
| Affected | 22.2.4151 |
| Affected | 22.2.4134 |
| Affected | 22.1.4113 |
| Affected | 21.4.4072 |
| Affected | 21.3.4055 |
Versions not listed are: unaffected.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
Fortinet FortiSandbox contains an OS command injection vulnerability that could allow an unauthenticated attacker to execute unauthorized code or commands via crafted HTTP requests.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2026-39808 to its Known Exploited Vulnerabilities (KEV) catalog on 16 Jul 2026.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 19 Jul 2026.
- The CVE record was published on 14 Apr 2026, 93 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 9.1 (Critical), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 93.2% (percentile 99.8), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
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 <insert attack vector here>
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CVE record last updated | |
| CISA due date for the required action |
References
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