CVE-2026-39808
Confirmed PUBLISHEDA improper neutralization of special elements used in an os command ('os command injection') vulnerability in Fortinet FortiSandbox 4.4.0 through...
34 days faster than CISA KEV
Recommended Action
Prioritize immediate patching and validate internet-facing exposure. Monitor for matching exploitation attempts in your environment.
At a Glance
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
- CVE Published
- Apr 14, 2026
- Exploitation Reported
- Jun 12, 2026
- CVSS
- 9.1 Critical
- EPSS
- 89.7%
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| Fortinet |
FortiSandbox
|
4.4.0 to <= 4.4.8 |
Affected |
| Fortinet |
FortiSandbox PaaS
|
23.4.4374 |
Affected |
| Fortinet |
FortiSandbox PaaS
|
23.4.4350 |
Affected |
| Fortinet |
FortiSandbox PaaS
|
23.3.4329 |
Affected |
| Fortinet |
FortiSandbox PaaS
|
23.1.4245 |
Affected |
| Fortinet |
FortiSandbox PaaS
|
22.2.4151 |
Affected |
| Fortinet |
FortiSandbox PaaS
|
22.2.4134 |
Affected |
| Fortinet |
FortiSandbox PaaS
|
22.1.4113 |
Affected |
| Fortinet |
FortiSandbox PaaS
|
21.4.4072 |
Affected |
| Fortinet |
FortiSandbox PaaS
|
21.3.4055 |
Affected |
CVE References
- https://fortiguard.fortinet.com/psirt/FG-IR-26-100 fortiguard.fortinet.com · CVE Record https://fortiguard.fortinet.com/psirt/FG-IR-26-100
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| KEVIntel First | 2026-06-12 13:59 UTC |
| The Shadowserver | 2026-07-09 00:00 UTC |
| All CISA Advisories | 2026-07-16 12:00 UTC |
| CISA | 2026-07-16 17:00 UTC |
| CVE | 2026-07-16 17:51 UTC |
Operational indicators for this CVE are listed on the Detection tab.
Observed Exploitation Attempts
Exploitation attempts against this vulnerability observed first-hand by KEVIntel private honeypots over the last 30 days.
- Attempts Observed
- 492
- Unique Attacker IPs
- 56
- Attacker Countries
- 🇦🇷 🇦🇿 🇧🇬 🇨🇭 🇨🇳 🇩🇪 🇫🇮 🇫🇷 🇭🇰 🇮🇩 🇮🇹 🇯🇵 🇰🇷 🇲🇩 🇲🇾 🇳🇱 🇷🇺 🇸🇪 🇸🇬 🇺🇸 🇻🇺
- Sensors Observed
- 4
Exploitation Attempts Over the Last 48 Days
First observed (all time) 2026-06-12 13:59 UTC · Last observed 2026-07-27 16:54 UTC
See more exploitation detail
- Pro — sensor software/region breakdown and 24h/7d window summaries.
- Enterprise — raw attacker IPs, request paths, User-Agents, and payloads.
Indicators of Compromise (IoCs)
Attacker IP IoCs observed in KEVIntel sensors are available to Pro and Enterprise accounts on the Detection tab and through the Pro API.
Learn about Pro API accessObserved Detection Signals (30d)
Aggregate counts from KEVIntel sensor telemetry for this CVE.
- Distinct request paths
- 1
- Distinct User-Agents
- 29
The specific request paths and User-Agents attackers are using are available on Pro and Enterprise plans.
Scanner Artifacts
Scanner and exploit-framework references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-39808.yaml | Jun 01, 2026 |
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
Supported Platforms
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
GET /api/v2/enterprise/virtual_patches?cve_id=CVE-2026-39808
CVSS Scores
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
Exploitation Status
Exploited in the wild
Recorded 2026-06-12 13:59:12 UTC · KEVIntel
Active exploitation observed
Recorded 2026-06-12 13:59:12 UTC · KEVIntel sensor
Proof of concept available
Recorded 2026-06-12 14:21:13 UTC · Nuclei Templates
Weaknesses (CWE)
-
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Scanner Integrations
Nuclei, Metasploit, and other scanner references for this CVE are listed on the Detection tab.
Recent Mentions
All CISA Advisories · Jul 16, 2026
CISA has added three new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog, based on evidence of active exploitation. CVE-2026-25089 Fortinet FortiSandbox OS Command Injection Vulnerability CVE-2026-39808 Fortinet FortiSandbox OS Command Injection Vulnerability CVE-2026-58644 Microsoft SharePoint Deserialization of Untrusted Data Vulnerability These types of vulnerabilities are frequent attack vectors for malicious cyber actors and pose significant risks to the federal enterprise. Binding Operational Directive (BOD) 26-04: Prioritizing Security Updates Based on Risk establishes vulnerability management requirements for Federal Civilian Executive Branch (FCEB) agencies. BOD 26-04 reinforces the importance of the KEV Catalog and requires federal agencies to prioritize rapid remediation of high-risk vulnerabilities, specifically those identified by Common Vulnerabilities and Exposures (CVEs) listed in CISA’s KEV Catalog on publicly exposed assets that grant total control of the asset post-exploitation, while deferring action for lower-risk vulnerabilities. BOD 26-04 further establishes basic expectations for when agencies must check whether threat actors compromised the system before the patch was applied. While BOD 26-04 applies only to FCEB agencies, CISA encourages all organizations to adopt risk-based vulnerability management and prioritize remediation of KEV Catalog vulnerabilities. CISA will continue to add vulnerabilities to the catalog that meet the specified criteria. Aware of an exploited vulnerability not currently listed in the KEV Catalog? Submit it for potential addition through CISA’s KEV Nomination Form. Potential KEV additions must have a CVE ID, evidence of exploitation, and clear mitigation guidance.
TheHackerNews · Jun 16, 2026
Bad actors are exploiting multiple security vulnerabilities in Fortinet FortiSandbox, according to threat intelligence firm Defused Cyber. In a post shared on X, the company said it has observed exploitation of CVE-2026-39813, CVE-2026-39808, and CVE-2026-25089 over the past 24 hours. CVE-2026-39813 (CVSS score: 9.1) refers to a path traversal vulnerability in FortiSandbox JRPC API that could
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
github · Created 2026-06-18 20:32:26 UTC · 0 stars
Fortinet FortiSandbox 4.4.0-4.4.8 - OS Command Injection via tracer-behavior Endpoint
github · Created 2026-06-17 01:42:02 UTC · 0 stars
CVE-2026-39808 - Fortinet Sandbox - Draft
nuclei · Created Unknown
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
17:51 UTC 12 days ago17:51 UTC · 12 days ago
KEV confirmed by CVE
Exploitation attested by an external source
-
17:00 UTC 12 days ago17:00 UTC · 12 days ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
12:00 UTC 12 days ago12:00 UTC · 12 days ago
KEV confirmed by All CISA Advisories
Exploitation attested by an external source
-
00:00 UTC 20 days ago00:00 UTC · 20 days ago
KEV confirmed by The Shadowserver
Exploitation attested by an external source
-
14:21 UTC about 1 month ago14:21 UTC · about 1 month ago
Virtual patch available
Compensating WAF rule available to block exploitation
-
14:21 UTC about 2 months ago14:21 UTC · about 2 months ago
Public PoC available
Public proof-of-concept code published
-
13:59 UTC about 2 months ago13:59 UTC · about 2 months ago
Observed by KEVIntel sensors
Evidence-backed exploitation signal
-
13:59 UTC about 2 months ago13:59 UTC · about 2 months ago
Indicators of compromise added (56)
Indicators of compromise recorded
-
15:34 UTC about 2 months ago15:34 UTC · about 2 months ago
Nuclei template available
Scanner coverage available
-
15:38 UTC 3 months ago15:38 UTC · 3 months ago
CVE published
Vulnerability disclosed publicly
-
15:24 UTC 4 months ago15:24 UTC · 4 months ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2026-39808
{
"cve_id": "CVE-2026-39808",
"title": "A improper neutralization of special elements used in an os command (\'os comm...",
"affected_vendor": "Fortinet",
"affected_product": "FortiSandbox, FortiSandbox PaaS",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 9.1,
"epss_score": 0.89691,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": true
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}