CVE-2026-39808

Confirmed PUBLISHED

A improper neutralization of special elements used in an os command ('os command injection') vulnerability in Fortinet FortiSandbox 4.4.0 through...

Fortinet · FortiSandbox, FortiSandbox PaaS

34 days faster than CISA KEV

Exploited in the wild Active exploitation observed PoC available Virtual patch available

Recommended Action

Prioritize immediate patching and validate internet-facing exposure. Monitor for matching exploitation attempts in your environment.

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Confidence

Confirmed

Exploitation Status

Active exploitation observed

Observed in Sensors

Yes

Attempts (30d)

272

Unique Attacker IPs

CISA KEV

In CISA KEV

Virtual Patch

Yes 3 targets

CVSS / EPSS

9.1 Critical EPSS 84.2%

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

edge nuclei_scanner cisa

CVE Published: Apr 14, 2026
Exploitation Reported: Jun 12, 2026
CVSS: 9.1 Critical
EPSS: 84.2%

Remote Low complexity No user interaction Unauthenticated

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

Recommended Actions

Prioritize immediate patching and validate internet-facing exposure. Monitor for matching exploitation attempts in your environment.
Review sensor telemetry for request paths, attacker IPs, and payload patterns that may inform detection and exposure validation.
Check enrichment artifacts for scanner coverage and available PoCs before rolling remediation validation.
Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.

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.

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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.

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.

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Observed Detection Signals (30d)

Aggregate counts from KEVIntel sensor telemetry for this CVE.

Distinct request paths: 1
Distinct User-Agents: 25

The specific request paths and User-Agents attackers are using are available on Pro and Enterprise plans.

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Scanner Artifacts

Nuclei and Metasploit 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

CVSS Scores

CVSS v3.1 9.1 Critical

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)

CWE-78

Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Scanner Integrations

Scanner	Reference	Detected
Nuclei	https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-39808.yaml	Jun 01, 2026

Recent Mentions

CISA Adds Three Known Exploited Vulnerabilities to Catalog

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.

Attackers Exploit Three Fortinet FortiSandbox Flaws, One Patched Last Week

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.

error-inside/CVE-2026-39808

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

HORKimhab/CVE-2026-39808

github · Created 2026-06-17 01:42:02 UTC · 0 stars

CVE-2026-39808 - Fortinet Sandbox - Draft

Fortinet FortiSandbox - Command Injection

nuclei · Created Unknown

Timeline

Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.

16 Jul 2026 17:51 UTC 3 days ago

16 Jul 2026 17:51 UTC · 3 days ago

KEV confirmed by CVE

Exploitation attested by an external source
16 Jul 2026 17:00 UTC 3 days ago

16 Jul 2026 17:00 UTC · 3 days ago

Added to CISA KEV

Listed in the CISA Known Exploited Vulnerabilities catalog
16 Jul 2026 12:00 UTC 3 days ago

16 Jul 2026 12:00 UTC · 3 days ago

KEV confirmed by All CISA Advisories

Exploitation attested by an external source
9 Jul 2026 00:00 UTC 10 days ago

9 Jul 2026 00:00 UTC · 10 days ago

KEV confirmed by The Shadowserver

Exploitation attested by an external source
22 Jun 2026 14:21 UTC 27 days ago

22 Jun 2026 14:21 UTC · 27 days ago

Virtual patch available

Compensating WAF rule available to block exploitation
12 Jun 2026 14:21 UTC about 1 month ago

12 Jun 2026 14:21 UTC · about 1 month ago

Public PoC available

Public proof-of-concept code published
12 Jun 2026 13:59 UTC about 1 month ago

12 Jun 2026 13:59 UTC · about 1 month ago

Observed by KEVIntel sensors

Evidence-backed exploitation signal
12 Jun 2026 13:59 UTC about 1 month ago

12 Jun 2026 13:59 UTC · about 1 month ago

Indicators of compromise added (47)

Indicators of compromise recorded
1 Jun 2026 15:34 UTC about 2 months ago

1 Jun 2026 15:34 UTC · about 2 months ago

Nuclei template available

Scanner coverage available
14 Apr 2026 15:38 UTC 3 months ago

14 Apr 2026 15:38 UTC · 3 months ago

CVE published

Vulnerability disclosed publicly
7 Apr 2026 15:24 UTC 3 months ago

7 Apr 2026 15:24 UTC · 3 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.

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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": 0.84158,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "...": "Pro API fields" },
  "proof_of_concepts": [ "..." ],
  "scanner_integrations": [ "..." ]
}

The free JSON API returns basic KEV fields only. Confidence, telemetry, and artifact enrichment require Pro API access.

CVE-2026-39808

At a Glance

Affected Versions

CVE References

Recommended Actions

Known Exploited Vulnerability Sources

Observed Exploitation Attempts

Exploitation Attempts Over the Last 39 Days

See more exploitation detail

Indicators of Compromise (IoCs)

Observed Detection Signals (30d)

Scanner Artifacts

Virtual Patch

Supported Platforms

CVSS Scores

Exploitation Status

Weaknesses (CWE)

Scanner Integrations

Recent Mentions

Potential Proof of Concepts

Timeline

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