Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.70 and 9.7.0-alpha.18, an authenticated user with find class-level permission can bypass the protectedFields class-level permission setting on LiveQuery subscriptions. By sending a subscription with a $or, $and, or $nor operator value as a plain object with numeric keys and a length property (an "array-like" object) instead of an array, the protected-field guard is bypassed. The subscription event firing acts as a binary oracle, allowing the attacker to infer whether a protected field matches a given test value. This issue has been patched in versions 8.6.70 and 9.7.0-alpha.18.
https://github.com/parse-community/parse-server/security/advisories/GHSA-mmg8-87c5-jrc2
https://github.com/parse-community/parse-server/pull/10351
https://github.com/parse-community/parse-server/pull/10350
https://github.com/parse-community/parse-server/commit/ffad0ec6b971ee0dd9545e1bf1fb34ddebf275c2
https://github.com/parse-community/parse-server/commit/f63fd1a3fe0a7c1c5fe809f01b0e04759e8c9b98
Published: 2026-03-31
Updated: 2026-04-02
Base Score: 4
Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:N/A:N
Severity: Medium
Base Score: 4.3
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Severity: Medium
Base Score: 5.3
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00045