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.

CVSS v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/parse-community/parse-server/commit/9b94083accb7f3e72c6b8126c195c7a03dd2dfd7	Patch
https://github.com/parse-community/parse-server/commit/9d5942d50e55c822924c27b05aa98f1393e7a330	Patch
https://github.com/parse-community/parse-server/releases/tag/8.6.3	Release Notes
https://github.com/parse-community/parse-server/releases/tag/9.3.1-alpha.4	Release Notes
https://github.com/parse-community/parse-server/security/advisories/GHSA-4q3h-vp4r-prv2	Patch Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:parseplatform:parse-server::::::node.js::*
	cpe:2.3:a:parseplatform:parse-server::::::node.js::*
	cpe:2.3:a:parseplatform:parse-server:9.3.1:alpha1::::node.js::*
	cpe:2.3:a:parseplatform:parse-server:9.3.1:alpha2::::node.js::*
	cpe:2.3:a:parseplatform:parse-server:9.3.1:alpha3::::node.js::*

History

No history.

Information

Published : 2026-02-26 00:16

Updated : 2026-03-04 03:09

NVD link : CVE-2026-27804

Mitre link : CVE-2026-27804

CVE.ORG link : CVE-2026-27804

JSON object : View

Products Affected

parseplatform

parse-server

CWE

CWE-327

Use of a Broken or Risky Cryptographic Algorithm

CWE-345

Insufficient Verification of Data Authenticity

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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."}, {"lang": "es", "value": "Parse Server es un backend de c\u00f3digo abierto que puede implementarse en cualquier infraestructura que pueda ejecutar Node.js. Antes de las versiones 8.6.3 y 9.1.1-alpha.4, un atacante no autenticado puede falsificar un token de autenticaci\u00f3n de Google con 'alg: \"none\"' para iniciar sesi\u00f3n como cualquier usuario vinculado a una cuenta de Google, sin conocer sus credenciales. Todas las implementaciones con autenticaci\u00f3n de Google habilitada se ven afectadas. La correcci\u00f3n en las versiones 8.6.3 y 9.1.1-alpha.4 codifica de forma r\u00edgida el algoritmo 'RS256' esperado en lugar de confiar en el encabezado JWT, y reemplaza el recuperador de claves personalizado del adaptador de Google con 'jwks-rsa' que rechaza los ID de clave desconocidos. Como soluci\u00f3n alternativa, deshabilite la autenticaci\u00f3n de Google hasta que sea posible la actualizaci\u00f3n."}], "lastModified": "2026-03-04T03:09:41.600", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:parseplatform:parse-server:*:*:*:*:*:node.js:*:*", "vulnerable": true, "matchCriteriaId": "6013714D-C959-4E21-90BC-38DB536DDD7A", "versionEndExcluding": "8.6.3"}, {"criteria": "cpe:2.3:a:parseplatform:parse-server:*:*:*:*:*:node.js:*:*", "vulnerable": true, "matchCriteriaId": "6DF6F6EE-4C02-49CB-9B73-D8C2A567DC5A", "versionEndExcluding": "9.3.1", "versionStartIncluding": "9.0.0"}, {"criteria": "cpe:2.3:a:parseplatform:parse-server:9.3.1:alpha1:*:*:*:node.js:*:*", "vulnerable": true, "matchCriteriaId": "DF17F1D3-1FF0-4F19-AF82-A8866CE625D3"}, {"criteria": "cpe:2.3:a:parseplatform:parse-server:9.3.1:alpha2:*:*:*:node.js:*:*", "vulnerable": true, "matchCriteriaId": "98AB1B71-E3FD-457A-AA25-074E2F5A0581"}, {"criteria": "cpe:2.3:a:parseplatform:parse-server:9.3.1:alpha3:*:*:*:node.js:*:*", "vulnerable": true, "matchCriteriaId": "C73893F8-315F-4FE3-9ADB-DD2965797C46"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}