CVE-2026-39813
Confirmed PUBLISHEDA path traversal: '../filedir' vulnerability in Fortinet FortiSandbox 5.0.0 through 5.0.5, FortiSandbox 4.4.0 through 4.4.8 may allow attacker to...
Not yet in CISA KEV
Recommended Action
Prioritize immediate patching and validate internet-facing exposure. Monitor for matching exploitation attempts in your environment.
At a Glance
A path traversal: '../filedir' vulnerability in Fortinet FortiSandbox 5.0.0 through 5.0.5, FortiSandbox 4.4.0 through 4.4.8 may allow attacker to escalation of privilege via specially crafted HTTP requests.
- CVE Published
- Apr 14, 2026
- Exploited Since
- Jun 15, 2026
- CVSS
- 9.1 Critical
- EPSS
- 16.7%
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| Fortinet |
FortiSandbox
|
5.0.0 to <= 5.0.5 |
Affected |
| Fortinet |
FortiSandbox
|
4.4.0 to <= 4.4.8 |
Affected |
| Fortinet |
FortiSandbox Cloud
|
24.1 |
Affected |
| Fortinet |
FortiSandbox Cloud
|
23.4 |
Affected |
| Fortinet |
FortiSandbox Cloud
|
5.0.4 to <= 5.0.5 |
Affected |
CVE References
- https://fortiguard.fortinet.com/psirt/FG-IR-26-112 fortiguard.fortinet.com · CVE Record https://fortiguard.fortinet.com/psirt/FG-IR-26-112
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.
Learn about Pro API access| Source | Added |
|---|---|
| Defused Cyber First | 2026-06-16 15:17 UTC |
| KEVIntel | 2026-06-15 12:48 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
- 53
- Unique Attacker IPs
- 12
- Attacker Countries
- 🇦🇿 🇧🇬 🇬🇧 🇭🇰 🇮🇳 🇱🇾 🇸🇪 🇸🇬 🇹🇷 🇺🇦 🇺🇸
- Sensors Observed
- 1
Exploitation Attempts Over the Last 36 Days
First observed (all time) 2026-06-15 12:48 UTC · Last observed 2026-07-03 08:23 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
- 4
- Distinct User-Agents
- 19
The specific request paths and User-Agents attackers are using are available on Pro and Enterprise plans.
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-2026-39813
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 2026-06-16 15:17:57 UTC · Defused Cyber
Active exploitation observed
Recorded 2026-06-15 12:48:52 UTC · KEVIntel sensor
Proof of concept available
Recorded 2026-04-21 17:10:00 UTC · GitHub
Weaknesses (CWE)
-
Path Traversal: '../filedir'
Recent Mentions
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 2026-06-17 01:41:17 UTC · 0 stars
CVE-2026-39813 - Fortinet Sandbox - Draft
public · Created 2026-04-21 17:10:00 UTC
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
14:21 UTC 27 days ago14:21 UTC · 27 days ago
Virtual patch available
Compensating WAF rule available to block exploitation
-
15:17 UTC about 1 month ago15:17 UTC · about 1 month ago
Added to KEVIntel KEV Feed
High-confidence, third-party attested exploitation
-
12:48 UTC about 1 month ago12:48 UTC · about 1 month ago
Observed by KEVIntel sensors
Evidence-backed exploitation signal
-
12:48 UTC about 1 month ago12:48 UTC · about 1 month ago
Indicators of compromise added (12)
Indicators of compromise recorded
-
17:10 UTC 3 months ago17:10 UTC · 3 months ago
Public PoC available
Public proof-of-concept code published
-
15:38 UTC 3 months ago15:38 UTC · 3 months ago
CVE published
Vulnerability disclosed publicly
-
15:24 UTC 3 months ago15:24 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.
Pro API Example
GET /api/v2/pro/kevs/CVE-2026-39813
{
"cve_id": "CVE-2026-39813",
"title": "A path traversal: \'../filedir\' vulnerability in Fortinet FortiSandbox 5.0.0 t...",
"affected_vendor": "Fortinet",
"affected_product": "FortiSandbox, FortiSandbox Cloud",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 9.1,
"epss_score": 0.16739,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": true
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}