CVE-2026-30939

Description

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

How to fix CVE-2026-30939

To remediate CVE-2026-30939, upgrade the affected package to a fixed version below.

• —upgrade to 8.6.13 or later
• —upgrade to 8.6.13 or later

Is CVE-2026-30939 being exploited?

Low — EPSS is 0.2%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 8.6.13, >= 9.0.0, < 9.5.1
• from 0, < 8.6.13

CVSS scores

References (5)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2026-30939
• PATCHgithub.com/parse-community/parse-server
• WEBgithub.com/parse-community/parse-server/releases/tag/8.6.13
• WEBgithub.com/parse-community/parse-server/releases/tag/9.5.1-alpha.2