CVSS 4.0
9.3 criticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:NCVE-2026-27804
Critical (9.3) in parseplatform parse-server. EPSS 0.2% chance of exploitation in the next 30 days. Fixed in parse-server 8.6.3, 9.3.1-alpha.4.
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.
Severity
CVSS 3.1
9.1 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N- EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 9% of CVEs (scores of 2026-10-31)
- CWEs
- CWE-327, CWE-345
- Published
- Modified
- Record from
- the NVD, synced
Affected
- parseplatform:parse-server
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-4q3h-vp4r-prv2 | npm | parse-server | >=9.0.0 <9.3.1-alpha.4 | 9.3.1-alpha.4 |
| GHSA-4q3h-vp4r-prv2 | npm | parse-server | <8.6.3 | 8.6.3 |
References
- 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