CVE-2026-33421

Description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.53 and 9.6.0, Parse Server's LiveQuery WebSocket interface does not enforce Class-Level Permission (CLP) pointer permissions (readUserFields and pointerFields). Any authenticated user can subscribe to LiveQuery events and receive real-time updates for all objects in classes protected by pointer permissions, regardless of whether the pointer fields on those objects point to the subscribing user. This bypasses the intended read access control, allowing unauthorized access to potentially sensitive data that is correctly restricted via the REST API. This issue has been patched in versions 8.6.53 and 9.6.0

How to fix CVE-2026-33421

To remediate CVE-2026-33421, upgrade the affected package to a fixed version below.

• —upgrade to 8.6.53 or later
• —upgrade to 9.6.0-alpha.42 or later

Is CVE-2026-33421 being exploited?

Low — EPSS is 0.4%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 8.6.53, >= 9.0.0, < 9.6.0
• >= 9.0.0, < 9.6.0-alpha.42

CVSS scores

References (7)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2026-33421
• PATCHgithub.com/parse-community/parse-server
• WEBgithub.com/parse-community/parse-server/commit/6c3317aca6eb618ac48f999021ae3ef7766ad1ea
• WEBgithub.com/parse-community/parse-server/commit/976dad109f3fe3fbd0a3a35ef62e7a5d35eb0bee