CVE-2026-27804 Parse Server: Account takeover via JWT algorithm confusion in Google auth adapter
Unauthenticated attackers can forge Google JWTs to take over accounts in Parse Server deployments with Google auth enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-27804?
CVE-2026-27804 is a critical authentication bypass vulnerability in Parseplatform Parse-Server, published on 25 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-27804?
5 open source packages ship an affected version, including parse-server and parse. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
parse-server npm | All versions | 8.6.3 |
parse-server npm | All versions | 8.6.3 |
parse-server npm | From 9.0.0 | 9.3.1-alpha.4 |
parse-server npm | From 9.0.0 | 9.3.1-alpha.4 |
parse Bitnami | All versions | 8.6.3, 9.3.1 |
Products include Parseplatform Parse-Server.
How do I fix CVE-2026-27804?
Upgrade parse-server to a fixed version for your release line: 8.6.3 or 9.3.1-alpha.4.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-27804 being exploited?
There is no known exploitation of CVE-2026-27804 in the wild and no public exploit code.
Other vulnerabilities in Parseplatform Parse-Server
- CVE-2026-30966 Parse Server role escalation and CLP bypass via direct `_Join` table write
- CVE-2024-27298 Parse Server literalizeRegexPart SQL Injection
- CVE-2022-24760 Command Injection in Parse server
- CVE-2026-30965 Parse Server session token exfiltration via `redirectClassNameForKey` query parameter
- CVE-2023-36475 Parse Server vulnerable to remote code execution via MongoDB BSON parser through prototype pollution
Sources
Also known as BIT-parse-2026-27804, GHSA-4q3h-vp4r-prv2.