7.6

CVSS Score

4.0

-

CVSS Score

Basic Information

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CVE-2026-30967

CVE-2026-30967: Parse Server OAuth2 authentication adapter account takeover via identity spoofing

Impact

The OAuth2 authentication adapter, when configured without the useridField option, only verifies that a token is active via the provider's token introspection endpoint, but does not verify that the token belongs to the user identified by authData.id. An attacker with any valid OAuth2 token from the same provider can authenticate as any other user.

This affects any Parse Server deployment that uses the generic OAuth2 authentication adapter (configured with oauth2: true) without setting the useridField option.

Patches

The vulnerability is fixed by defaulting useridField to sub, which is the standard subject identifier field defined by RFC 7662. The adapter now always validates the token's identity against the claimed user ID, even when useridField is not explicitly configured.

Workarounds

Set the useridField option to the appropriate field name for your OAuth2 provider (e.g. sub) in the Parse Server authentication configuration.

References

GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-fr88-w35c-r596
Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.5.2-alpha.9
Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.22

(GitHub Advisory)

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CVE-2026-30967

CVE-2026-30967:

7.6

CVSS Score

4.0

-

CVSS Score

Basic Information

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Technical Details

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
parse-server	npm	>= 9.0.0-alpha.1, < 9.5.2-alpha.9	9.5.2-alpha.9
parse-server	npm	< 8.6.22	8.6.22

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability exists in the OAuth2 authentication adapter of Parse Server. When the useridField option was not specified in the server configuration, the validateAuthData function would not check if the user ID from the OAuth2 token introspection response matched the user ID being claimed in the authentication request (authData.id). This allowed an attacker who possessed any valid token from the same OAuth2 provider to authenticate as any other user on the Parse Server instance. The patch addresses this by modifying the validateOptions function to default the useridField to 'sub', which is the standard field for the subject identifier in an OAuth2 token. This ensures that the user ID check in validateAuthData is always performed, preventing the identity spoofing attack.

Vulnerable functions

OAuth2Adapter.validateAuthData

src/Adapters/Auth/oauth2.js

This function was vulnerable because it would only perform user ID validation if the `useridField` was explicitly configured. If not, it would only validate the token's activity, allowing an attacker with any valid token to impersonate another user by providing their user ID.

OAuth2Adapter.validateOptions

src/Adapters/Auth/oauth2.js

This function is where the fix was applied. By not having a default value for `useridField`, it allowed the validation in `validateAuthData` to be bypassed. The patch ensures that `useridField` defaults to 'sub', enforcing the user ID check.

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WAF Rule

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Reasoning

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