CVE-2025-11287 is a medium-severity vulnerability affecting samanhappy MCPHub versions 0.9.0 through 0.9.10. The flaw exists in the handleSseConnection function within the src/services/sseService.ts file, where improper authentication logic allows an attacker to bypass authentication controls. This vulnerability can be exploited remotely without requiring any authentication or user interaction, making it accessible to unauthenticated attackers over the network. The improper authentication likely allows unauthorized users to establish Server-Sent Events (SSE) connections, potentially gaining access to sensitive real-time data streams or functionalities intended only for authenticated users. The vulnerability has a CVSS 4.0 base score of 6.9, reflecting a medium severity level due to its network attack vector, no required privileges or user interaction, but limited impact on confidentiality, integrity, and availability (each rated low). The vendor was notified early but has not responded or issued patches, and no official fixes or mitigations are currently available. Exploit code is publicly available, increasing the risk of exploitation, although no known active exploitation has been reported in the wild to date. The vulnerability’s presence in multiple versions indicates a longstanding issue in the MCPHub product line.

For European organizations using samanhappy MCPHub, this vulnerability poses a significant risk of unauthorized access to SSE-based services, potentially exposing sensitive operational or business data transmitted via these channels. The improper authentication could allow attackers to intercept or manipulate real-time data streams, leading to confidentiality breaches or data integrity issues. While the direct impact on system availability appears limited, unauthorized access could facilitate further lateral movement or privilege escalation within affected environments. Given the lack of vendor response and patches, European entities relying on MCPHub for critical infrastructure or business processes may face prolonged exposure. This risk is heightened in sectors where real-time data integrity and confidentiality are paramount, such as finance, telecommunications, and industrial control systems. Additionally, the public availability of exploit code lowers the barrier for attackers, increasing the likelihood of targeted attacks against vulnerable European deployments.

European organizations should immediately audit their MCPHub deployments to identify affected versions (0.9.0 through 0.9.10). Until an official patch is released, organizations should implement compensating controls such as network segmentation to isolate MCPHub servers from untrusted networks and restrict access to trusted IP ranges only. Deploying Web Application Firewalls (WAFs) or Intrusion Prevention Systems (IPS) with custom rules to detect and block suspicious SSE connection attempts can reduce exposure. Monitoring network traffic for anomalous SSE connection patterns and unauthorized access attempts is critical. Organizations should also consider disabling or restricting SSE functionality if feasible, or migrating to alternative solutions with stronger authentication mechanisms. Regularly reviewing and updating access control policies and ensuring robust logging and alerting on MCPHub services will aid in early detection of exploitation attempts. Engaging with the vendor for updates and tracking vulnerability disclosures is essential for timely patch application once available.