CVE-2026-27804

Parse Server versions prior to 8.6.3 and 9.1.1-alpha.4 are vulnerable to unauthenticated login via forged Google tokens (alg: none). The root cause is trusting the JWT header for algorithm selection; the fix hardcodes RS256 and shifts key validation to jwks-rsa, rejecting unknown key IDs. Affecte...

GHSA-4Q3H-VP4R-PRV2 Parse Server: Account takeover via JWT algorithm confusion in Google auth adapter

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...