CVE-2025-40658 is an Insecure Direct Object Reference (IDOR) vulnerability identified in the DM Corporative CMS developed by Dmacroweb. The vulnerability is categorized under CWE-639, which relates to authorization bypass through user-controlled keys. Specifically, the issue arises in the /administer/selectionnode/framesSelection.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 areas of the CMS. This flaw allows an unauthenticated attacker to bypass authorization controls without requiring any user interaction or privileges. The vulnerability has a CVSS 4.0 base score of 6.9 (medium severity), indicating a network-exploitable issue with low complexity and no need for authentication or user interaction. The impact is primarily on confidentiality, as unauthorized access to private administrative areas could expose sensitive data or configuration settings. However, integrity and availability impacts are not indicated. No known exploits are currently reported in the wild, and no patches have been published yet. The vulnerability was reserved in April 2025 and published in June 2025, suggesting it is a recent discovery. The affected version is listed as '0', which likely refers to an initial or early release of the DM Corporative CMS product. The vulnerability's exploitation vector is remote and straightforward, making it a significant risk if the product is deployed in production environments without mitigations.

For European organizations using DM Corporative CMS, this vulnerability poses a risk of unauthorized access to sensitive administrative areas, potentially exposing confidential business data, user information, or internal configurations. Such exposure could lead to further attacks, including data theft, privilege escalation, or disruption of CMS operations. Given the CMS nature, organizations in sectors like government, finance, healthcare, and critical infrastructure that rely on this software for content management could face reputational damage, regulatory penalties (e.g., GDPR violations), and operational disruptions. The medium severity score reflects a moderate but tangible risk, especially since exploitation does not require authentication or user interaction. The absence of known exploits in the wild provides a window for proactive mitigation. However, the ease of exploitation means that threat actors could develop exploits rapidly once the vulnerability becomes widely known. European organizations should assess their exposure based on the deployment of DM Corporative CMS and prioritize remediation to prevent unauthorized access and potential data breaches.

1. Immediate mitigation should include restricting access to the /administer/selectionnode/framesSelection.asp endpoint via network controls such as IP whitelisting or VPN-only access to limit exposure to trusted users. 2. Implement web application firewall (WAF) rules to detect and block requests with suspicious 'option' parameter values (0, 1, 2) targeting this endpoint. 3. Conduct a thorough audit of user access controls and ensure that authorization checks are properly enforced server-side, not relying solely on client-side or parameter-based controls. 4. Monitor logs for unusual access patterns or repeated attempts to manipulate the 'option' parameter. 5. Engage with the vendor (Dmacroweb) to obtain patches or updates addressing this vulnerability as soon as they become available. 6. If patching is delayed, consider isolating the CMS environment or deploying compensating controls such as multi-factor authentication for administrative access. 7. Educate administrators and security teams about this vulnerability to increase vigilance against potential exploitation attempts.