GitHub Advisoryadvisory · npm

GHSA-4q3h-vp4r-prv2 Parse Server: Account takeover via JWT algorithm confusion in Google auth adapter

CRITICAL Published 2026-02-25 Modified 2026-02-27 Official page ↗
Aliases
CVE-2026-27804
Ecosystem
npm
Packages
parse-server
Severity
Critical
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Weaknesses
CWE-327, CWE-345
Reviewed
2026-02-25

Affected packages

• npm parse-server: >= 9.0.0, < 9.3.1-alpha.4 → fixed in 9.3.1-alpha.4 • npm parse-server: < 8.6.3 → fixed in 8.6.3

Description

Impact 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. Patches The fix 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. Workarounds Disable Google authentication until you can upgrade. References • GitHub advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-4q3h-vp4r-prv2 • Fixed in Parse Server 9.3.1-alpha.4: https://github.com/parse-community/parse-server/releases/tag/9.3.1-alpha.4 • Fixed in Parse Server 8.6.3: https://github.com/parse-community/parse-server/releases/tag/8.6.3

Related

Alias · CVE (1)

  • CVE-2026-27804 Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. vulnerability

Weakness · CWE (2)

  • CWE-327 Use of a Broken or Risky Cryptographic Algorithm weakness
  • CWE-345 Insufficient Verification of Data Authenticity weakness

References