CVE-2025-52487 is a high-severity security vulnerability affecting the Dnn.Platform, an open-source web content management system widely used within the Microsoft ecosystem. The vulnerability exists in versions 7.0.0 up to, but not including, 10.0.1. It stems from an incorrect authorization flaw (CWE-863) in the implementation of the DNN Login IP Filters feature. This feature is designed to restrict login attempts to a predefined allow list of IP addresses, thereby enhancing security by limiting access to trusted sources. However, due to this vulnerability, an attacker can craft a specially designed request or proxy that bypasses these IP restrictions, allowing login attempts from unauthorized IP addresses that are not on the allow list. The vulnerability does not require any authentication or user interaction, and can be exploited remotely over the network with low attack complexity. The impact on confidentiality is high, as unauthorized access could lead to data exposure or unauthorized administrative control. Integrity and availability impacts are lower but still present, as unauthorized access could lead to unauthorized changes or disruptions. The vulnerability has been patched in version 10.0.1 of Dnn.Platform. No known exploits are currently reported in the wild, but the high CVSS 4.0 score of 8.8 reflects the significant risk posed by this flaw if exploited.

For European organizations using Dnn.Platform versions prior to 10.0.1, this vulnerability poses a significant risk of unauthorized access. Attackers could bypass IP-based login restrictions, potentially gaining administrative access to CMS backends. This could lead to data breaches, defacement of websites, insertion of malicious content, or pivoting to internal networks. Organizations in sectors such as government, finance, healthcare, and critical infrastructure that rely on Dnn.Platform for web content management are particularly at risk. The breach of confidentiality could expose sensitive personal data protected under GDPR, leading to regulatory penalties and reputational damage. Additionally, the integrity of public-facing websites could be compromised, undermining trust and operational continuity. Since exploitation requires no authentication or user interaction and can be performed remotely, the attack surface is broad, increasing the likelihood of targeted or opportunistic attacks. The absence of known exploits currently provides a window for proactive mitigation before widespread exploitation occurs.

1. Immediate upgrade: Organizations should prioritize upgrading all Dnn.Platform instances to version 10.0.1 or later, where the vulnerability is patched. 2. Network-level controls: Implement additional network-level access controls such as firewall rules or VPN restrictions to limit access to the CMS login interfaces to trusted IPs, adding a defense-in-depth layer beyond the application-level IP filters. 3. Monitoring and logging: Enhance monitoring of login attempts and access logs for unusual patterns, especially login attempts from unexpected IP addresses or geographic locations. 4. Web Application Firewall (WAF): Deploy or update WAF rules to detect and block suspicious requests that attempt to bypass IP filtering mechanisms. 5. Incident response readiness: Prepare incident response procedures to quickly address any signs of compromise related to this vulnerability, including account lockouts and forensic analysis. 6. Configuration review: Review and tighten other authentication and authorization configurations within Dnn.Platform to reduce the risk of privilege escalation. 7. User awareness: Educate administrators about the vulnerability and the importance of timely patching and monitoring.