# CVE-2026-27804

## Summary

- **CVE ID:** CVE-2026-27804
- **Severity:** CRITICAL
- **CVSS Score:** 9.3 (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)
- **CWE:** CWE-327, CWE-345
- **Published:** Feb 25, 2026
- **Last Modified:** Mar 12, 2026

## Description

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 Products

- parse-community — parse-server (>= 9.0.0, < 9.3.1-alpha.4)
- parse-community — parse-server (< 8.6.3)

## References

- [CNA](https://github.com/parse-community/parse-server/security/advisories/GHSA-4q3h-vp4r-prv2)
- [CNA](https://github.com/parse-community/parse-server/commit/9b94083accb7f3e72c6b8126c195c7a03dd2dfd7)
- [CNA](https://github.com/parse-community/parse-server/commit/9d5942d50e55c822924c27b05aa98f1393e7a330)
- [CNA](https://github.com/parse-community/parse-server/releases/tag/8.6.3)
- [CNA](https://github.com/parse-community/parse-server/releases/tag/9.3.1-alpha.4)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.18%
- **EPSS Percentile:** 7.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._