CVE-2026-27804

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.

The following products are affected by CVE-2026-27804 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-27804.

URL	Resource
https://github.com/parse-community/parse-server/commit/9b94083accb7f3e72c6b8126c195c7a03dd2dfd7
https://github.com/parse-community/parse-server/commit/9d5942d50e55c822924c27b05aa98f1393e7a330
https://github.com/parse-community/parse-server/releases/tag/8.6.3
https://github.com/parse-community/parse-server/releases/tag/9.3.1-alpha.4
https://github.com/parse-community/parse-server/security/advisories/GHSA-4q3h-vp4r-prv2