CVE-2026-41473

Executive Summary

CVE-2026-41473 is a critical authentication bypass vulnerability affecting CyberPanel versions prior to 2.4.4. The flaw resides in the AI Scanner worker API endpoints, specifically /api/ai-scanner/status-webhook and /api/ai-scanner/callback. An unauthenticated remote attacker can exploit the lack of authentication checks to write arbitrary data to the database. This can lead to denial of service through storage exhaustion, corruption of scan history records, and pollution of database fields with malicious data. The vulnerability has a CVSS score of 0.0 (likely uncalculated or placeholder), but based on the impact, it is considered critical. No public proof-of-concept (PoC) code or exploit is currently available, but the attack vector is straightforward due to the missing authentication.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The vulnerability is exploitable remotely over the network.
• Attack Complexity (AC): Low (L) – No special conditions or complex steps are required.
• Privileges Required (PR): None (N) – No authentication is needed.
• User Interaction (UI): None (N) – No user action is required.
• Scope (S): Unchanged (U) – The exploit does not affect other components.
• Confidentiality (C): None (N) – No data is read.
• Integrity (I): High (H) – Arbitrary data can be written to the database.
• Availability (A): High (H) – Storage exhaustion can cause denial of service.

Threat Level: Critical. The lack of authentication allows any remote attacker to inject data, corrupt records, and exhaust storage, leading to significant operational impact.

Deep Dive & Mechanics

The vulnerability exists in the AI Scanner worker API endpoints of CyberPanel. These endpoints are designed to receive status updates and callbacks from the AI scanning service. However, they lack any authentication or authorization checks, allowing any unauthenticated HTTP request to be processed.

The affected endpoints are:

• /api/ai-scanner/status-webhook
• /api/ai-scanner/callback

An attacker can send crafted POST requests to these endpoints with arbitrary JSON payloads. The server will then write this data directly to the database without validation. This can be used to:

• Fill the database with large amounts of data, causing storage exhaustion and denial of service.
• Overwrite or corrupt existing scan history records.
• Inject malicious data into database fields, potentially affecting other parts of the application.

The vulnerability is particularly dangerous because it requires no authentication and can be exploited by any remote attacker with network access to the CyberPanel instance.

Vulnerable vs. Patched Code

Vulnerable Code (pre-2.4.4): The vulnerable code likely lacks any authentication middleware or token validation for the AI scanner endpoints. For example, a simplified vulnerable handler might look like:

@app.route('/api/ai-scanner/status-webhook', methods=['POST'])
def status_webhook():
    data = request.json
    # Directly write to database without authentication
    db.insert('scan_status', data)
    return 'OK', 200

Patched Code (2.4.4+): The patched version adds authentication checks, such as requiring an API key or token. For example:

@app.route('/api/ai-scanner/status-webhook', methods=['POST'])
def status_webhook():
    token = request.headers.get('Authorization')
    if not token or token != expected_token:
        return 'Unauthorized', 401
    data = request.json
    # Validate and sanitize data before writing
    if validate_data(data):
        db.insert('scan_status', data)
        return 'OK', 200
    else:
        return 'Bad Request', 400

The patch ensures that only authenticated requests from the legitimate AI scanner service are processed.

Exploitation & Lab Setup

Red Team

Exploitation Steps:

1. Identify a target running CyberPanel version < 2.4.4.
2. Send a crafted POST request to the /api/ai-scanner/status-webhook or /api/ai-scanner/callback endpoint.
3. Include arbitrary JSON data to pollute the database or cause storage exhaustion.

Example Exploit (using curl):

curl -X POST http://target.com/api/ai-scanner/status-webhook \
  -H "Content-Type: application/json" \
  -d '{"scan_id": "malicious", "status": "completed", "data": "A"*1000000}'

Note: No public exploit code is available, but the attack is trivial to execute.

Blue Team

Detection and Response:

• Monitor for unexpected POST requests to /api/ai-scanner/status-webhook and /api/ai-scanner/callback from unknown IPs.
• Look for large payloads or unusual JSON structures in these endpoints.
• Check database for unexpected entries in scan-related tables.
• Implement network segmentation to restrict access to the CyberPanel admin interface.

Honeypot Setup:

• Deploy a honeypot that mimics the vulnerable endpoints to capture attacker behavior.
• Log all requests to these endpoints for analysis.

Indicators of Compromise (IOCs)

• Network IOCs:

  • POST requests to /api/ai-scanner/status-webhook or /api/ai-scanner/callback from external IPs.
  • Large HTTP request bodies (e.g., >1MB) to these endpoints.
  • Unusual JSON fields in the request body (e.g., "malicious_data": "...").

• Host IOCs:

  • Unexpected entries in the CyberPanel database tables related to AI scanner scans.
  • High disk usage due to database bloat.
  • Corrupted or invalid scan history records.

• Log IOCs:

  • Web server logs showing 200 responses to unauthenticated POST requests to the vulnerable endpoints.
  • Database logs showing large inserts from unknown sources.

Detection Engineering

YARA Rule

rule CVE_2026_41473_Exploit {
    meta:
        description = "Detects exploit attempts for CVE-2026-41473 in CyberPanel"
        author = "Valters IT"
        date = "2026-01-01"
        reference = "CVE-2026-41473"
    strings:
        $endpoint1 = "/api/ai-scanner/status-webhook"
        $endpoint2 = "/api/ai-scanner/callback"
        $json_body = /{"[^}]*"scan_id"[^}]*"status"[^}]*}/
    condition:
        any of ($endpoint*) and $json_body
}

Sigma Rule

title: CyberPanel AI Scanner Authentication Bypass Exploit
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects unauthenticated POST requests to CyberPanel AI Scanner endpoints
author: Valters IT
date: 2026-01-01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem:
            - '/api/ai-scanner/status-webhook'
            - '/api/ai-scanner/callback'
    condition: selection
falsepositives:
    - Legitimate AI scanner service (if authenticated)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2026-41473 CyberPanel AI Scanner Authentication Bypass"; flow:to_server; content:"POST"; http_method; content:"/api/ai-scanner/status-webhook"; http_uri; nocase; content:"/api/ai-scanner/callback"; http_uri; nocase; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade CyberPanel to version 2.4.4 or later.
2. If immediate upgrade is not possible, restrict access to the vulnerable endpoints using a web application firewall (WAF) or network ACLs.
3. Monitor logs for any suspicious activity targeting these endpoints.

Long-Term Mitigations:

• Implement authentication for all API endpoints.
• Use input validation and sanitization for all data written to the database.
• Regularly audit and review API security.
• Deploy intrusion detection systems (IDS) to detect exploitation attempts.

Patch Details:

• Upgrade to CyberPanel version 2.4.4, which includes authentication checks for the AI scanner endpoints.

Valters IT

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