Parse Server is an open-source backend framework that runs on Node.js and is widely used to build mobile and web applications. In versions prior to 8.6.9 and 9.5.0-alpha.9, the file metadata endpoint (GET /files/:appId/metadata/:filename) does not enforce the beforeFind and afterFind triggers, which are typically used to implement access control policies on file data. These triggers act as gatekeepers to restrict unauthorized access to files based on custom logic defined by developers. However, the metadata endpoint bypasses these triggers entirely, resulting in missing authorization checks (CWE-862). Consequently, an attacker can retrieve metadata information about files without proper permissions. This metadata could include sensitive details such as file names, sizes, types, and timestamps, potentially aiding further attacks or information gathering. The vulnerability is remotely exploitable without authentication or user interaction, increasing its risk profile. The issue was publicly disclosed in March 2026 and has been patched in the specified versions. No active exploitation has been observed, but the vulnerability's presence in widely deployed parse-server instances poses a risk to confidentiality of file metadata.

The primary impact of CVE-2026-30850 is unauthorized disclosure of file metadata, which can compromise confidentiality. While the vulnerability does not allow direct access to file contents, metadata can reveal sensitive information about stored files, such as naming conventions, file sizes, and timestamps, which can be leveraged for reconnaissance or to facilitate further attacks. Organizations relying on parse-server for backend services may inadvertently expose sensitive metadata to unauthorized parties, undermining trust and potentially violating data protection policies. This can affect applications handling personal data, intellectual property, or other sensitive information. The vulnerability's ease of exploitation without authentication increases the risk of automated scanning and data harvesting by attackers. Although no known exploits are currently reported in the wild, the widespread use of parse-server in mobile and web applications globally means many organizations could be affected if they have not applied patches. The impact is primarily on confidentiality, with no direct effect on integrity or availability.

To mitigate CVE-2026-30850, organizations should immediately upgrade parse-server to version 8.6.9 or later, or 9.5.0-alpha.9 or later, where the issue is patched. Beyond upgrading, developers should audit their use of beforeFind and afterFind triggers to ensure that all file-related endpoints, including metadata endpoints, enforce consistent access control policies. Implement additional server-side authorization checks specifically for the metadata endpoint to prevent unauthorized access. Employ network-level protections such as firewall rules and API gateways to restrict access to backend services to trusted clients. Monitor logs for unusual access patterns to file metadata endpoints that could indicate exploitation attempts. Consider encrypting sensitive metadata fields if feasible to reduce information leakage. Finally, maintain an up-to-date inventory of parse-server instances and their versions to ensure timely patch management.