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.
https://github.com/parse-community/parse-server/security/advisories/GHSA-j7mm-f4rv-6q6q
https://github.com/parse-community/parse-server/releases/tag/9.6.0-alpha.9
https://github.com/parse-community/parse-server/releases/tag/8.6.35
Published: 2026-03-11
Updated: 2026-03-13
Base Score: 7.8
Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:N/A:N
Severity: High
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Severity: High
Base Score: 6.9
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00041