Parse Server: Cloud function validator bypass via prototype chain traversal

Summary

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.

Timeline

1. Mar 31, 2026, 2:42 PM UTCCVE published
2. Mar 31, 2026, 5:21 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Mar 31, 2026, 5:21 PM UTCRecord last updated

Affected versions

• parse-community parse-server

  fixed in 8.6.67; From 9.0.0 · fixed in 9.7.0-alpha.11

• parse-servernpm

  From 9.0.0 · fixed in 9.7.0-alpha.11

• parse-servernpm

  fixed in 8.6.67

References 5