CVE-2026-30939

Workarounds

Place a reverse proxy or WAF in front of Parse Server and block requests to Object.prototype property names.

References

• GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-5j86-7r7m-p8h6
• Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.5.1-alpha.2
• Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.13

An unauthenticated attacker can crash the Parse Server process by calling a Cloud Function endpoint with a prototype property name as the function name. The server recurses infinitely, causing a call stack size error that terminates the process.

Other prototype property names bypass Cloud Function dispatch validation and return HTTP 200 responses, even though no such Cloud Functions are defined. The same applies to dot-notation traversal.

All Parse Server deployments that expose the Cloud Function endpoint are affected.

Kodem intelligence

The internal handler registries for Cloud Functions, Jobs, Triggers, and Validators have been changed to prevent prototype chain properties from being resolved.

1. What is CVE-2026-30939? CVE-2026-30939 is a high-severity security vulnerability in parse-server (npm), affecting versions < 8.6.13. It is fixed in 8.6.13, 9.5.1-alpha.2.
2. Which versions of parse-server are affected by CVE-2026-30939? parse-server (npm) versions < 8.6.13 is affected.
3. Is there a fix for CVE-2026-30939? Yes. CVE-2026-30939 is fixed in 8.6.13, 9.5.1-alpha.2. Upgrade to this version or later.
4. Is CVE-2026-30939 exploitable, and should I be worried? Whether CVE-2026-30939 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-2026-30939 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-2026-30939?
   • Upgrade parse-server to 8.6.13 or later
   • Upgrade parse-server to 9.5.1-alpha.2 or later

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