CVE-2026-27804

The record

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.

Affected packages

Related vulnerabilities

• GHSA-4q3h-vp4r-prv2 Parse Server: Account takeover via JWT algorithm confusion in Google auth adapter Same vulnerability
• GHSA-97pr-9hgg-3p8r parse-server: LiveQuery discloses object data to a subscriber across an ACL read-access… Also affects parse-server
• GHSA-wmwx-jr2p-4j4r parse-server: Relation `$relatedTo` query bypasses `protectedFields` and owning-object ACL Also affects parse-server
• GHSA-7wqv-xjf3-x35v parse-server: Stored XSS via trailing-dot filename bypassing file upload extension… Also affects parse-server
• GHSA-p84r-h6rx-f2xr parse-server: Server option routeAllowList is bypassable through batch sub-requests Also affects parse-server
• GHSA-cgxm-vr2f-6fj8 parse-server: Denial of service via exponential-time processing of deeply nested query… Also affects parse-server
• CVE-2026-53726 Parse Server is an open source backend that can be deployed to any infrastructure that… Also affects parse-server
• CVE-2026-53724 Parse Server is an open source backend that can be deployed to any infrastructure that… Also affects parse-server