CVE-2026-33409: Parse server Parse Server Has An Auth Vulnerability

HIGH
Advisory Identifier: GHSA-pfj7-wv7c-22pr
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CVSS 9.1
CWE-287
Published
Advisory Summary

CVE-2026-33409 is a HIGH (CVSS 9.1) parse server has an auth vulnerability (CWE-287: Improper Authentication) affecting Parse server libraries in the npm ecosystem. The issue involves parse server has an auth provider validation bypass on login via partial authdata. Remediation is available by upgrading affected packages to version 9.6.0-alpha.41, 8.6.52.

CVE-2026-33409 at a Glance

CVE Identifier CVE-2026-33409
GHSA Identifier GHSA-pfj7-wv7c-22pr
Severity HIGH
CVSS v3.1 Base Score 9.1
CWE Classification CWE-287: Improper Authentication
Affected Product Parse server
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 9.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-33409

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: 9.6.0-alpha.41 
npm install parse-server@9.6.0-alpha.41
parse-server fixed: 8.6.52 
npm install parse-server@8.6.52
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-2026-33409, 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 9.6.0-alpha.41), 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-287: Improper Authentication, where when an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. 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 authentication bypass vulnerability allows an attacker to log in as any user who has linked a third-party authentication provider, without knowing the user's credentials. The attacker only needs to know the user's provider ID to gain full access to their account, including a valid session token. This affects Parse Server deployments where the server option `allowExpiredAuthDataToken` is set to `true`. The default value is `false`. ### Patches Auth providers are now always validated on login, regardless of the `allowExpiredAuthDataToken` setting. The option `allowExpiredAuthDataToken` has been deprecated and will be removed in a future major version. ### Workarounds Set `allowExpiredAuthDataToken` to `false` (the default) or remove the option from the server configuration.

CVE-2026-33409 Affected Parse server Versions

2 component(s)
Fixed Versions:
9.6.0-alpha.418.6.52
Product / Package Ecosystem Affected Versions Fixed Version
parse-server
npm/parse-server
npm
≥ 9.0.0
< 9.6.0-alpha.41
9.6.0-alpha.41
parse-server
npm/parse-server
npm
< 8.6.52
8.6.52

References

GitHub Advisory / Wiki ADVISORY
https://github.com/parse-community/parse-server/security/advisories/GHSA-pfj7-wv7c-22pr
NVD — CVE-2026-33409 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33409
Parse server Source Repository REPOSITORY
https://github.com/parse-community/parse-server/pull/10246
Parse server Source Repository REPOSITORY
https://github.com/parse-community/parse-server/pull/10247
Security Fix Commit FIX COMMIT
https://github.com/parse-community/parse-server/commit/8d7df5639c4a35768fe8b78b4580b30e8a74721c
Security Fix Commit FIX COMMIT
https://github.com/parse-community/parse-server/commit/98f4ba5bcf2c199bfe6225f672e8edcd08ba732d
Parse server Source Repository REPOSITORY
https://github.com/parse-community/parse-server

Frequently Asked Questions

What is CVE-2026-33409?
CVE-2026-33409 is a security vulnerability in Parse server involving Parse Server has an auth provider validation bypass on login via partial authData under CWE-287: Improper Authentication.
Which Parse server versions are affected?
Affected versions include releases prior to 9.6.0-alpha.41, 8.6.52 across affected packages: parse-server.
What version fixes CVE-2026-33409?
Upgrading to 9.6.0-alpha.41, 8.6.52 (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 9.6.0-alpha.41, 8.6.52. Upgrade your dependency to 9.6.0-alpha.41, 8.6.52 or later.
What is the CVSS score of CVE-2026-33409?
CVE-2026-33409 has a CVSS v3.1 base score of 9.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2026-33409?
CVE-2026-33409 is classified under CWE-287: Improper Authentication (When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.).
How can I check npm dependencies for CVE-2026-33409?
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-pfj7-wv7c-22pr",
  "modified" : "2026-03-30T13:51:12Z",
  "published" : "2026-03-19T21:32:10Z",
  "aliases" : [ "CVE-2026-33409" ],
  "summary" : "Parse Server has an auth provider validation bypass on login via partial authData",
  "details" : "### Impact\n\nAn authentication bypass vulnerability allows an attacker to log in as any user who has linked a third-party authentication provider, without knowing the user's credentials. The attacker only needs to know the user's provider ID to gain full access to their account, including a valid session token.\n\nThis affects Parse Server deployments where the server option `allowExpiredAuthDataToken` is set to `true`. The default value is `false`.\n\n### Patches\n\nAuth providers are now always validated on login, regardless of the `allowExpiredAuthDataToken` setting. The option `allowExpiredAuthDataToken` has been deprecated and will be removed in a future major version.\n\n### Workarounds\n\nSet `allowExpiredAuthDataToken` to `false` (the default) or remove the option from the server configuration.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "parse-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0"
      }, {
        "fixed" : "9.6.0-alpha.41"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "parse-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "8.6.52"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/security/advisories/GHSA-pfj7-wv7c-22pr"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-33409"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/pull/10246"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/pull/10247"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/commit/8d7df5639c4a35768fe8b78b4580b30e8a74721c"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/commit/98f4ba5bcf2c199bfe6225f672e8edcd08ba732d"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/parse-community/parse-server"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-287" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-19T21:32:10Z",
    "nvd_published_at" : "2026-03-24T19:16:53Z"
  }
}