CVE-2026-34532 CRITICAL

CVE-2026-34532: Parse Server: Cloud function validator bypass via prototype chain traversal

Vendor Parse-Community
Product parse-server
Weakness CWE-863 · Incorrect authorization
Published March 31, 2026
Last update March 31, 2026

CVSS base score

9.1/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

01Description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.67 and 9.7.0-alpha.11, an attacker can bypass Cloud Function validator access controls by appending "prototype.constructor" to the function name in the URL. When a Cloud Function handler is declared using the function keyword and its validator is a plain object or arrow function, the trigger store traversal resolves the handler through its own prototype chain while the validator store fails to mirror this traversal, causing all access control enforcement to be skipped. This allows unauthenticated callers to invoke Cloud Functions that are meant to be protected by validators such as requireUser, requireMaster, or custom validation logic. This issue has been patched in versions 8.6.67 and 9.7.0-alpha.11.

Key dates

02Disclosure timeline

March 31, 2026 CVE published
March 31, 2026 Record updated