CVE-2026-53726
MediumCVSS 6.9Exploitation Probability (EPSS)
Low risk19th percentile - higher than 19% of all known CVEs
Summary
In Parse Server prior to versions 8.6.80 and 9.9.1-alpha.6, a vulnerability allowed reading the membership of a Relation field using the $relatedTo operator, even when that field was hidden from the client. This enabled unauthorized clients to enumerate objects linked through a protected relation.
Risk Assessment
Organizations may be exposed to the disclosure of sensitive membership information, potentially leading to privacy violations and unauthorized data access.
Recommendation
It is recommended to upgrade Parse Server to versions 8.6.80 or 9.9.1-alpha.6 to mitigate this vulnerability and review the security of applications using protected fields and ACLs.
Original NVD description (English source)
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.80 and 9.9.1-alpha.6, a relation query using the $relatedTo operator could read the membership of a Relation field even when that field was hidden from the requesting client by protectedFields, and even when the object owning the relation was not readable by the client under its ACL or class-level permissions. The request requires only the public API credentials that Parse clients normally carry — no user session, master key, or Cloud Code is needed. As a result, an unauthenticated client who knows or obtains the owning object's objectId could enumerate the objects linked through a protected relation, or combine the operator with an objectId constraint to use it as a membership oracle — confirming whether a specific object is linked to a private parent. This affects applications that rely on protectedFields or object ACLs to keep Relation membership confidential, such as private group memberships, block lists, or account-to-resource associations. This issue has been patched in versions 8.6.80 and 9.9.1-alpha.6.