Vulnerability Description
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.3 and 9.1.1-alpha.4, an unauthenticated attacker can forge a Google authentication token with `alg: "none"` to log in as any user linked to a Google account, without knowing their credentials. All deployments with Google authentication enabled are affected. The fix in versions 8.6.3 and 9.1.1-alpha.4 hardcodes the expected `RS256` algorithm instead of trusting the JWT header, and replaces the Google adapter's custom key fetcher with `jwks-rsa` which rejects unknown key IDs. As a workaround, dsable Google authentication until upgrading is possible.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Parseplatform | Parse-Server | < 8.6.3 |
Related Weaknesses (CWE)
References
- https://github.com/parse-community/parse-server/commit/9b94083accb7f3e72c6b8126cPatch
- https://github.com/parse-community/parse-server/commit/9d5942d50e55c822924c27b05Patch
- https://github.com/parse-community/parse-server/releases/tag/8.6.3Release Notes
- https://github.com/parse-community/parse-server/releases/tag/9.3.1-alpha.4Release Notes
- https://github.com/parse-community/parse-server/security/advisories/GHSA-4q3h-vpPatchVendor Advisory
FAQ
What is CVE-2026-27804?
CVE-2026-27804 is a vulnerability with a CVSS score of 9.1 (CRITICAL). Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.3 and 9.1.1-alpha.4, an unauthenticated attacker can forge a Google authen...
How severe is CVE-2026-27804?
CVE-2026-27804 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-27804?
Check the references section above for vendor advisories and patch information. Affected products include: Parseplatform Parse-Server.