CVE-2026-33409

Description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.52 and 9.6.0, an authentication bypass vulnerability allows an attacker to log in as any user who has linked a third-party authentication provider, without knowing the user's credentials. The attacker only needs to know the user's provider ID to gain full access to their account, including a valid session token. This affects Parse Server deployments where the server option allowExpiredAuthDataToken is set to true. The default value is false. This issue has been patched in versions 8.6.52 and 9.6.0

How to fix CVE-2026-33409

To remediate CVE-2026-33409, upgrade the affected package to a fixed version below.

• —upgrade to 8.6.52 or later
• —upgrade to 9.6.0-alpha.41 or later

Is CVE-2026-33409 being exploited?

Low — EPSS is 0.5%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 8.6.52, >= 9.0.0, < 9.6.0
• >= 9.0.0, < 9.6.0-alpha.41

CVSS scores

References (7)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2026-33409
• PATCHgithub.com/parse-community/parse-server
• WEBgithub.com/parse-community/parse-server/commit/8d7df5639c4a35768fe8b78b4580b30e8a74721c
• WEBgithub.com/parse-community/parse-server/commit/98f4ba5bcf2c199bfe6225f672e8edcd08ba732d