Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 9.6.0-alpha.9 and 8.6.35, an attacker can exploit LiveQuery subscriptions to infer the values of protected fields without directly receiving them. By subscribing with a WHERE clause that references a protected field (including via dot-notation or $regex), the attacker can observe whether LiveQuery events are delivered for matching objects. This creates a boolean oracle that leaks protected field values. The attack affects any class that has both protectedFields configured in Class-Level Permissions and LiveQuery enabled. This vulnerability is fixed in 9.6.0-alpha.9 and 8.6.35.
Exploitability
AV:NAC:LAT:NPR:NUI:NVulnerable System
VC:LVI:NVA:NSubsequent System
SC:NSI:NSA:N6.9/CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:NInformation Disclosure