CVE-2026-66008 in parse-server
Summary
by MITRE • 07/24/2026
Parse Server versions >= 9.0.0 before 9.10.0-alpha.6 and >= 8.2.2 before 8.6.87 disclose Pointer and Relation target class names through GraphQL validation and input-coercion error messages when public schema introspection is disabled (graphQLPublicIntrospection: false, the default). Because these errors are produced before authentication, authorization, or any resolver runs, an unauthenticated client possessing only the public application ID can trigger errors on Pointer or Relation fields to reconstruct hidden schema class names, partially defeating the schema-hiding protection. Only schema metadata (class names) is exposed; no object data, credentials, or user records are disclosed.
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Analysis
by VulDB Data Team • 07/24/2026
This vulnerability affects Parse Server versions between 9.0.0 and 9.10.0-alpha.6, as well as versions 8.2.2 through 8.6.87, where the GraphQL validation and input-coercion error messages inadvertently reveal class names associated with Pointer and Relation fields even when public schema introspection is disabled. The flaw resides in how the system handles error generation for GraphQL queries that reference non-existent or improperly structured pointer relationships, specifically when these errors occur during the early stages of query processing before any authentication or authorization checks take place. This represents a direct violation of the principle of least privilege and information hiding, as attackers can exploit this weakness to reconstruct portions of the underlying database schema without proper credentials or permissions.
The technical mechanism behind this vulnerability stems from the GraphQL implementation's error handling procedures which do not adequately sanitize error messages that contain internal schema metadata. When an unauthenticated client submits a GraphQL query containing malformed Pointer or Relation field references, the server generates error responses that include class name information as part of the validation failure details. Since these errors are produced before any resolver execution or access control enforcement occurs, they bypass all normal security boundaries and provide attackers with valuable information about the hidden schema structure. This behavior directly maps to CWE-209, which addresses information exposure through error messages, and demonstrates a classic case of insufficient error handling that reveals internal system state.
The operational impact of this vulnerability is significant for applications relying on Parse Server's schema hiding capabilities as a security control mechanism. While the disclosure is limited to class names rather than actual data or credentials, it provides attackers with sufficient information to understand the application's data model architecture and potentially plan more sophisticated attacks. The exposure of hidden schema elements undermines the effectiveness of the default security configuration where graphQLPublicIntrospection is set to false, effectively neutralizing the intended protection against unauthorized schema discovery. This vulnerability particularly affects systems where sensitive data organization and structure are considered confidential information, as it allows attackers to map out relationships between different data entities without proper authorization.
Organizations should immediately upgrade to Parse Server versions 9.10.0-alpha.6 or later for the 9.x series, or 8.6.87 and later for the 8.x series to remediate this vulnerability. Additionally, administrators should review their current GraphQL configuration settings to ensure that public introspection remains disabled and consider implementing additional monitoring for unusual GraphQL query patterns that might indicate schema reconnaissance attempts. The fix implemented in these updated versions addresses the root cause by ensuring that error messages generated during GraphQL validation do not include class name information when the public introspection setting is disabled, thereby maintaining the intended security boundaries and preventing information leakage through error responses. This remediation aligns with best practices outlined in the OWASP Top Ten for 2021 and represents a critical security improvement for applications relying on Parse Server's GraphQL capabilities while maintaining the system's core functionality and performance characteristics.