CVE-2026-30967

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

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.

The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.

Kodem intelligence

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.

1. What is CVE-2026-30967? CVE-2026-30967 is a high-severity improper authentication vulnerability in parse-server (npm), affecting versions >= 9.0.0-alpha.1, < 9.5.2-alpha.9. It is fixed in 9.5.2-alpha.9, 8.6.22. The application does not adequately verify the identity of a user, device, or process before granting access.
2. Which versions of parse-server are affected by CVE-2026-30967? parse-server (npm) versions >= 9.0.0-alpha.1, < 9.5.2-alpha.9 is affected.
3. Is there a fix for CVE-2026-30967? Yes. CVE-2026-30967 is fixed in 9.5.2-alpha.9, 8.6.22. Upgrade to this version or later.
4. Is CVE-2026-30967 exploitable, and should I be worried? Whether CVE-2026-30967 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
5. What actually determines whether CVE-2026-30967 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
6. How do I fix CVE-2026-30967?
   • Upgrade parse-server to 9.5.2-alpha.9 or later
   • Upgrade parse-server to 8.6.22 or later

Other vulnerabilities in parse-server