Parse Server before 8.6.105 and 9.0.0 before 9.10.5-alpha.6 does not validate the owning object reference in $relatedTo relation queries, so supplying a query operator instead of an object ID bypasses the owning-object ACL check. A client with read access to at least one object of the owning class can disclose which readable objects are linked to owning objects it cannot read.

Parse Server before 8.6.105 and 9.0.0 before 9.10.5-alpha.6 does not validate the owning object reference in $relatedTo relation queries, so supplying a query operator instead of an object ID bypasses the owning-object ACL check. A client with read access to at least one object of the owning class can disclose which readable objects are linked to owning objects it cannot read.