CVE-2026-30939: Parse server Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-5j86-7r7m-p8h6
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CWE-1321
Published
Advisory Summary

CVE-2026-30939 is a HIGH denial of service vulnerability (CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')) affecting Parse server libraries in the npm ecosystem. The issue involves parse server has denial of service (dos) and cloud function dispatch bypass via prototype chain resolution. Remediation is available by upgrading affected packages to version 8.6.13, 9.5.1-alpha.2.

CVE-2026-30939 at a Glance

CVE Identifier CVE-2026-30939
GHSA Identifier GHSA-5j86-7r7m-p8h6
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Affected Product Parse server
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-30939

To remediate this vulnerability, upgrade all affected Parse server dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

parse-server fixed: 8.6.13 
npm install parse-server@8.6.13
parse-server fixed: 9.5.1-alpha.2 
npm install parse-server@9.5.1-alpha.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls parse-server

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-30939, inspect your project dependencies using npm:

npm ls parse-server

Analyze the terminal output to locate any version of Parse server in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 8.6.13), your application is affected.

Note: The npm ls parse-server command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution'), where the product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. In Parse server, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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

CVE-2026-30939 Affected Parse server Versions

2 component(s)
Fixed Versions:
8.6.139.5.1-alpha.2
Product / Package Ecosystem Affected Versions Fixed Version
parse-server
npm/parse-server
npm
< 8.6.13
8.6.13
parse-server
npm/parse-server
npm
≥ 9.0.0-alpha.1
< 9.5.1-alpha.2
9.5.1-alpha.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/parse-community/parse-server/security/advisories/GHSA-5j86-7r7m-p8h6
NVD — CVE-2026-30939 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-30939
Parse server Source Repository REPOSITORY
https://github.com/parse-community/parse-server
Parse server Release RELEASE
https://github.com/parse-community/parse-server/releases/tag/8.6.13
Parse server Release RELEASE
https://github.com/parse-community/parse-server/releases/tag/9.5.1-alpha.2

Frequently Asked Questions

What is CVE-2026-30939?
CVE-2026-30939 is a security vulnerability in Parse server involving Parse Server has Denial of Service (DoS) and Cloud Function Dispatch Bypass via Prototype Chain Resolution under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution').
Which Parse server versions are affected?
Affected versions include releases prior to 8.6.13, 9.5.1-alpha.2 across affected packages: parse-server.
What version fixes CVE-2026-30939?
Upgrading to 8.6.13, 9.5.1-alpha.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is parse-server affected?
Yes, parse-server is affected in releases prior to 8.6.13, 9.5.1-alpha.2. Upgrade your dependency to 8.6.13, 9.5.1-alpha.2 or later.
What CWE is associated with CVE-2026-30939?
CVE-2026-30939 is classified under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') (The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.).
How can I check npm dependencies for CVE-2026-30939?
Run the dependency tree command: 'npm ls parse-server'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5j86-7r7m-p8h6",
  "modified" : "2026-03-10T18:44:51Z",
  "published" : "2026-03-10T00:57:57Z",
  "aliases" : [ "CVE-2026-30939" ],
  "summary" : "Parse Server has Denial of Service (DoS) and Cloud Function Dispatch Bypass via Prototype Chain Resolution",
  "details" : "### Impact\n\nAn 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.\n\nOther 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.\n\nAll Parse Server deployments that expose the Cloud Function endpoint are affected.\n\n### Patches\n\nThe internal handler registries for Cloud Functions, Jobs, Triggers, and Validators have been changed to prevent prototype chain properties from being resolved.\n\n### Workarounds\n\nPlace a reverse proxy or WAF in front of Parse Server and block requests to `Object.prototype` property names.\n\n### References\n\n- GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-5j86-7r7m-p8h6\n- Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.5.1-alpha.2\n- Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.13",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "parse-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "8.6.13"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "parse-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0-alpha.1"
      }, {
        "fixed" : "9.5.1-alpha.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/security/advisories/GHSA-5j86-7r7m-p8h6"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-30939"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/parse-community/parse-server"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/releases/tag/8.6.13"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/releases/tag/9.5.1-alpha.2"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1321" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-10T00:57:57Z",
    "nvd_published_at" : "2026-03-10T18:18:53Z"
  }
}