CVE-2026-27804
CVE-2026-27804 · Parse Server: Account takeover via JWT algorithm confusion in Google auth adapter
This page contains facts from public vulnerability sources. Check the original advisory before updating.
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 9.3 · Critical · EPSS 0.2% · Fix available
- Published
- Updated
Stack: node
Affected products and versions
parse-server
- Versions
- >= 9.0.0, < 9.3.1-alpha.4: Affected
- < 8.6.3: Affected
No fix published
parse-server npm
- Affected ranges
- SEMVER: ≥ 9.0.0, < 9.3.1-alpha.4
Update to 9.3.1-alpha.4
parse-server npm
- Affected ranges
- SEMVER: < 8.6.3
Update to 8.6.3
Original sources
- https://github.com/parse-community/parse-server/security/advisories/GHSA-4q3h-vp4r-prv2
- 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://nvd.nist.gov/vuln/detail/CVE-2026-27804