CVE-2026-30854: Parse Server: GraphQL `__type` introspection bypass via inline fragments when public introspection is disabled
Impact
When graphQLPublicIntrospection is disabled, type queries nested inside inline fragments (e.g. ... on Query { type(name:"User") { name } }) bypass the introspection control, allowing unauthenticated users to perform type reconnaissance. schema introspection is not affected.
Patches
The check was changed from a flat iteration over root-level selections to a recursive walk of all selection sets, detecting type inside inline fragments at any depth.
Workarounds
Require master key authentication at the network layer (e.g. reverse proxy) for the GraphQL endpoint.
References
- GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-q5q9-2rhp-33qw - Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.5.0-alpha.10
Other sources
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. From version 9.3.1-alpha.3 to before version 9.5.0-alpha.10, when graphQLPublicIntrospection is disabled, type queries nested inside inline fragments (e.g. ... on Query { type(name:"User") { name } }) bypass the introspection control, allowing unauthenticated users to perform type reconnaissance. schema introspection is not affected. This issue has been patched in version 9.5.0-alpha.10.
— MITRE
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-30854?
CVE-2026-30854 is considered a moderate severity vulnerability due to its potential for bypassing GraphQL introspection.
How do I fix CVE-2026-30854?
To fix CVE-2026-30854, you should upgrade Parse Server to version 9.5.0-alpha.10 or later.
What is the impact of CVE-2026-30854?
The impact of CVE-2026-30854 allows unauthorized users to access GraphQL schema details when public introspection is disabled.
Which versions of Parse Server are affected by CVE-2026-30854?
Parse Server versions from 9.3.1-alpha.3 up to, but not including, 9.5.0-alpha.10 are affected by CVE-2026-30854.
Is CVE-2026-30854 related to GraphQL functionality?
Yes, CVE-2026-30854 specifically involves a GraphQL introspection bypass issue in Parse Server.