CVE-2026-2750

Executive Summary

CVE-2026-2750 is a critical Improper Input Validation vulnerability in the Centreon Open Tickets module running on the Centreon Central Server on Linux. This flaw allows an unauthenticated attacker to send specially crafted input to the affected module, potentially leading to remote code execution, data exfiltration, or full compromise of the monitoring infrastructure. With a CVSS score of 9.1, the vulnerability is rated as Critical and affects all versions prior to 25.10, 24.10, and 24.04. No public proof-of-concept or patch is currently available, making this a high-priority zero-day for defenders.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects the Centreon Open Tickets module, which is a PHP-based component of the Centreon monitoring platform. The risk is primarily to on-premises deployments of Centreon Central Server.

CVSS Breakdown & Threat Level

• CVSS Score: 9.1 (Critical)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: High (I:H)
• Availability Impact: High (A:H)

The vector string indicates that an unauthenticated attacker can exploit this vulnerability remotely with low complexity, leading to full compromise of confidentiality, integrity, and availability.

Deep Dive & Mechanics

The vulnerability resides in the Centreon Open Tickets module, which is used to integrate ticketing systems with Centreon monitoring. The module fails to properly validate user-supplied input before processing it. This can allow an attacker to inject malicious data that is then interpreted by the backend, potentially leading to:

• Remote Code Execution (RCE): By injecting PHP code or shell commands through improperly sanitized fields.
• SQL Injection: If input is passed to database queries without proper escaping.
• Path Traversal: Allowing access to sensitive files on the server.

The exact attack vector is not publicly documented, but given the nature of improper input validation, it is likely that the vulnerability exists in one of the API endpoints or form handlers that accept user input for ticket creation or updates.

Vulnerable vs. Patched Code

Since no patch is available, a direct code comparison cannot be provided. However, based on the vulnerability type, the following general differences are expected:

Vulnerable Code (Example):

$input = $_POST['ticket_data'];
$result = execute_command("process_ticket " . $input);

Patched Code (Expected):

$input = $_POST['ticket_data'];
$sanitized = filter_var($input, FILTER_SANITIZE_STRING);
$result = execute_command("process_ticket " . escapeshellarg($sanitized));

The patched version would include proper input validation, sanitization, and escaping to prevent injection attacks.

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Deploy a vulnerable Centreon Central Server (version < 25.10, 24.10, or 24.04) on a Linux VM.
2. Install the Centreon Open Tickets module.
3. Ensure the server is accessible over the network.

Exploitation Steps:

1. Identify the vulnerable endpoint (e.g., /centreon/open-tickets/api.php).
2. Craft a malicious payload that exploits the input validation flaw. For example, if the vulnerability is command injection:

   POST /centreon/open-tickets/api.php HTTP/1.1
   Host: target
   Content-Type: application/x-www-form-urlencoded
   
   ticket_data=;id
   

3. Execute the payload and observe the response for command output.
4. Escalate to a reverse shell or further compromise.

Note: No public exploit code is available. The above is a hypothetical example based on common patterns.

Blue Team

Detection Steps:

1. Monitor for unusual HTTP requests to /centreon/open-tickets/ endpoints.
2. Look for payloads containing shell metacharacters (;, |, &, $(), etc.) in POST parameters.
3. Enable web application firewall (WAF) rules to block common injection patterns.
4. Review server logs for unexpected command execution or file access.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP POST requests to /centreon/open-tickets/api.php with suspicious parameters.
  • Outbound connections from the Centreon server to unknown IPs on unusual ports.
• File IOCs:
  • Unexpected files in /tmp/ or /var/www/html/ with recent timestamps.
  • Modified PHP files in the Centreon Open Tickets module directory.
• Process IOCs:
  • Unusual processes spawned by the web server user (e.g., www-data).
  • Execution of commands like id, whoami, or reverse shell commands.

Detection Engineering

YARA Rule

rule CVE_2026_2750_Centreon_Open_Tickets {
    meta:
        description = "Detects exploitation attempts for CVE-2026-2750 in Centreon Open Tickets"
        author = "Valters IT"
        date = "2025-04-10"
        severity = "critical"
    strings:
        $suspicious_param = /ticket_data[^&]*[;|&$`]/
        $centreon_path = "/centreon/open-tickets/"
    condition:
        $centreon_path and $suspicious_param
}

Sigma Rule

title: CVE-2026-2750 Centreon Open Tickets Exploitation Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP requests targeting Centreon Open Tickets with potential injection payloads
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/centreon/open-tickets/*'
    keywords:
        - ';'
        - '|'
        - '&'
        - '$('
        - '`'
    condition: selection and keywords
falsepositives:
    - Legitimate use of special characters in ticket data
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2026-2750 Centreon Open Tickets Exploitation Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/centreon/open-tickets/"; http_uri; pcre:"/(;|\||&|\$\(|`)/Ri"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the Centreon Central Server from untrusted networks if possible.
2. Disable the Centreon Open Tickets module until a patch is available.
3. Implement strict input validation at the web server level (e.g., using ModSecurity rules).
4. Monitor logs for any signs of exploitation.

Long-term Fix:

• Apply the official patch from Centreon once released (expected in versions 25.10, 24.10, and 24.04).
• Upgrade to a patched version as soon as it becomes available.
• Conduct a security audit of all Centreon modules.

Workarounds:

• Use a reverse proxy to filter malicious requests.
• Restrict access to the Centreon web interface using VPN or IP whitelisting.

Valters IT