CVE-2025-53364 is a medium-severity vulnerability affecting the parse-server, an open-source backend framework widely used for building applications with Node.js infrastructure. The vulnerability exists in versions starting from 5.3.0 up to but not including 7.5.3, and from 8.0.0 up to but not including 8.2.2. It pertains to the GraphQL API component of parse-server, which previously allowed unauthenticated public access to the GraphQL schema introspection endpoint without requiring a session token or master key. Schema introspection in GraphQL reveals the structure and metadata of the API, including types, queries, mutations, and fields, but does not expose actual user data or content. Despite this, exposing schema metadata publicly can increase the attack surface by providing attackers with detailed knowledge about the backend data model and API capabilities, which can facilitate more targeted attacks such as injection, enumeration, or privilege escalation attempts. The vulnerability is classified under CWE-497, which involves exposure of sensitive system information to unauthorized entities. The CVSS 3.1 base score is 5.3 (medium), reflecting that the vulnerability can be exploited remotely without authentication or user interaction, but only results in limited confidentiality impact and no integrity or availability impact. No known exploits are currently reported in the wild. The issue was fixed in parse-server versions 7.5.3 and 8.2.2 by restricting access to schema introspection to authorized users only, requiring valid session tokens or master keys. Organizations using affected versions of parse-server should upgrade promptly to these fixed versions to eliminate the risk of schema metadata exposure.

For European organizations, the exposure of GraphQL schema metadata could aid attackers in reconnaissance activities, enabling them to better understand backend data structures and API operations. This knowledge can be leveraged to craft more effective attacks, such as injection attacks, unauthorized data access attempts, or privilege escalation exploits. While no direct data leakage occurs from schema introspection alone, the increased attack surface can indirectly lead to breaches if combined with other vulnerabilities or misconfigurations. Organizations handling sensitive or regulated data (e.g., personal data under GDPR) may face compliance risks if this vulnerability is exploited as part of a broader attack chain. Furthermore, organizations relying on parse-server for critical business applications could experience reputational damage and operational disruption if attackers leverage this information to compromise systems. The medium severity indicates that while the immediate risk is moderate, the potential for escalation exists, especially in complex environments where multiple vulnerabilities coexist.

To mitigate this vulnerability, European organizations should: 1) Immediately upgrade parse-server instances to version 7.5.3 or 8.2.2 or later, where the issue is fixed. 2) Review and restrict access controls on GraphQL endpoints to ensure that schema introspection is only accessible to authenticated and authorized users. 3) Implement network-level protections such as Web Application Firewalls (WAFs) to monitor and block unauthorized schema introspection requests. 4) Conduct thorough security assessments and penetration testing focused on GraphQL APIs to identify any additional weaknesses. 5) Monitor logs for unusual or repeated schema introspection queries from unknown or suspicious IP addresses. 6) Educate development and operations teams about the risks of exposing API metadata and enforce secure API design principles. 7) If immediate upgrade is not feasible, consider disabling GraphQL schema introspection or limiting it via custom middleware as a temporary workaround.