Overview
CVE-2026-39808 has been added to the CISA Known Exploited Vulnerabilities catalog. Published on April 14, 2026. Threat actors are actively exploiting this vulnerability in real-world attacks.
A improper neutralization of special elements used in an os command ('os command injection') vulnerability in Fortinet FortiSandbox 4.
Threat Intelligence
| Metric | Value |
|---|---|
| CVE ID | CVE-2026-39808 |
| Severity | HIGH |
| CVSS Score | 0.0/10 |
| CISA KEV | ✅ Yes — Actively Exploited |
| KEV Date Added | July 16, 2026 |
| Remediation Deadline | July 19, 2026 |
| EPSS Score | 48.7% exploit probability |
| EPSS Percentile | Top 99% of all CVEs |
Why This Matters
This vulnerability has been added to the CISA Known Exploited Vulnerabilities (KEV) catalog, which means threat actors are actively exploiting it in real-world attacks.
Federal agencies are required to remediate by July 19, 2026. All organizations should treat this deadline as a strong recommendation.
CISA Notes: https://fortiguard.fortinet.com/psirt/FG-IR-26-100 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: 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
Exploit Prediction (EPSS)
The FIRST EPSS model rates this vulnerability at 48.7% exploit probability (Moderate). This places it in the top 99% of all known CVEs by likelihood of exploitation in the next 30 days.
EPSS (Exploit Prediction Scoring System) uses real-world exploit data and machine learning to predict whether a vulnerability will be exploited. A high EPSS score is a strong signal to prioritize remediation.
Recommended Actions
- Verify exposure — Determine if your environment uses the affected software.
- Apply patches — Update to the latest version as soon as a fix is available.
- Monitor for compromise — Check logs for unusual activity.
- Meet the deadline — CISA recommends remediation by July 19, 2026.
References
CVE data aggregated from the National Vulnerability Database (NVD), CISA Known Exploited Vulnerabilities catalog, and FIRST EPSS. Analysis updated as new intelligence becomes available. Last updated: 2026-04-22.