CVE-2025-40659 is an Insecure Direct Object Reference (IDOR) vulnerability identified in the DM Corporative CMS developed by Dmacroweb. The vulnerability resides in the /administer/selectionnode/framesSelectionNetworks.asp endpoint, where an attacker can manipulate the 'option' parameter by setting it to values 0, 1, or 2 to gain unauthorized access to private administrative areas of the CMS. This flaw is categorized under CWE-639, which refers to Authorization Bypass Through User-Controlled Key, indicating that the application fails to properly verify user authorization when accessing sensitive resources based on user-supplied input. The vulnerability requires no authentication, user interaction, or privileges, and can be exploited remotely over the network, making it particularly dangerous. The CVSS 4.0 base score is 6.9 (medium severity), reflecting the ease of exploitation and the potential confidentiality impact, although integrity and availability impacts are minimal or none. Since the vulnerability allows unauthorized access to private administrative areas, attackers could potentially view or extract sensitive configuration data, user information, or other protected content managed by the CMS. However, there is no indication that the vulnerability allows modification or deletion of data, nor that it leads to remote code execution. No known exploits are currently reported in the wild, and no patches have been published yet. The affected version is listed as '0', which likely refers to an initial or early release version of the DM Corporative CMS. The vulnerability was reserved in April 2025 and published in June 2025, indicating recent discovery and disclosure.

For European organizations using DM Corporative CMS, this vulnerability poses a significant risk of unauthorized data exposure within administrative areas of their CMS installations. Confidential information such as internal configurations, user data, or business-sensitive content could be accessed by attackers without any authentication. This could lead to privacy violations, data leakage, and potentially facilitate further attacks by gathering intelligence on the CMS setup. Organizations in sectors with strict data protection regulations, such as finance, healthcare, or government, could face compliance issues and reputational damage if sensitive data is exposed. Although the vulnerability does not directly allow data modification or service disruption, the unauthorized access itself undermines the integrity of access controls and could be leveraged as a stepping stone for more advanced attacks. The lack of known exploits in the wild suggests limited immediate threat, but the ease of exploitation and absence of required privileges mean that attackers could quickly develop exploit tools once the vulnerability becomes widely known. European organizations relying on this CMS should prioritize assessment and mitigation to prevent potential breaches.

Since no official patches are currently available, organizations should implement compensating controls immediately. These include restricting access to the /administer/selectionnode/framesSelectionNetworks.asp endpoint via network-level controls such as IP whitelisting or VPN-only access to administrative interfaces. Web application firewalls (WAFs) should be configured to detect and block requests with suspicious 'option' parameter values (0, 1, or 2) targeting this endpoint. Additionally, organizations should audit CMS user permissions and ensure that administrative interfaces are not exposed to the public internet. Monitoring and logging access to this endpoint should be enhanced to detect any anomalous or unauthorized access attempts. Once a patch or update is released by Dmacroweb, organizations must apply it promptly. In the interim, consider isolating or disabling the vulnerable functionality if feasible without disrupting business operations. Regular security assessments and penetration testing focused on authorization controls can help identify similar weaknesses.