Parse Server CVE-2026-109302

Exploitation requires three concrete preconditions: (1) the Parse Server GraphQL API must be enabled and network-reachable; (2) the attacker must possess the public Application Id and a client key, which are distributed in client applications rather than kept secret; and (3) - the key limiting factor - an introspection query must already have been executed and cached in Apollo Server's automatic persisted query (APQ) cache by a master-key or maintenance-key client, since the attacker replays that cached operation rather than sending introspection text directly. This dependency on a pre-populated privileged cache entry (reflected as AT:P in the CVSS vector) significantly narrows real-world exploitability: on deployments where privileged clients never issue introspection, or where GraphQL is disabled, the attack does not succeed. Impact is limited to schema disclosure (private class and field names); no data modification or server compromise results.

This is a genuine but modest-priority issue - an information-disclosure (GraphQL schema introspection) weakness, not code execution or data compromise. The CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:N/UI:N) reports network reachability with no required privileges or user interaction, but critically includes AT:P (attack requirements): exploitation is NOT self-contained because it depends on an introspection query having been previously cached by a legitimate master-key or maintenance-key client. The only impact is VC:L (limited confidentiality) - disclosure of private class and field names - with no integrity or availability impact, consistent with the 6.3 Medium score and CWE-863 (Incorrect Authorization). No EPSS score, KEV listing, or POC was provided in the input, so there is no signal of active exploitation or weaponization; this is no public exploit identified at time of analysis. One nuance worth verifying: the description says 'unauthenticated attackers,' and the vector carries PR:N, yet the attacker must hold the public Application Id and client key - these are shared client-distribution credentials rather than per-user secrets, so PR:N is defensible, but defenders should note the attacker is not literally credential-less. Net: a real hardening priority for Parse Server operators exposing GraphQL, but a reconnaissance/disclosure flaw rather than a critical breach vector.

An attacker who has extracted the public Application Id and client key from a mobile or web app (both are client-distributed, non-secret values) sends introspection queries to the Parse Server GraphQL endpoint. Because Apollo Server's automatic persisted-query cache stores an introspection operation previously executed by a master- or maintenance-key client, the attacker replays that cached operation by hash and receives the full schema - including private class and field names - bypassing the introspection control. No public exploit code was identified at time of analysis, and success depends on a privileged client having already populated the APQ cache with an introspection query.