CVE-2026-31901: Parse server Parse Server Vulnerable To User Vulnerability

MODERATE
Advisory Identifier: GHSA-w54v-hf9p-8856
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CWE-204
Published
Advisory Summary

CVE-2026-31901 is a MODERATE parse server vulnerable to user vulnerability (CWE-204: Observable Response Discrepancy) affecting Parse server libraries in the npm ecosystem. The issue involves parse server vulnerable to user enumeration via email verification endpoint. Remediation is available by upgrading affected packages to version 9.6.0-alpha.8, 8.6.34.

CVE-2026-31901 at a Glance

CVE Identifier CVE-2026-31901
GHSA Identifier GHSA-w54v-hf9p-8856
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-204: Observable Response Discrepancy
Affected Product Parse server
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-31901

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.8 
npm install parse-server@9.6.0-alpha.8
parse-server fixed: 8.6.34 
npm install parse-server@8.6.34
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-2026-31901, 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.8), 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-204: Observable Response Discrepancy, where the product provides different responses to incoming requests in a way that reveals internal state information to an unauthorized actor outside of the intended control sphere. 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 The email verification endpoint (`/verificationEmailRequest`) returns distinct error responses depending on whether an email address belongs to an existing user, is already verified, or does not exist. An attacker can send requests with different email addresses and observe the error codes to determine which email addresses are registered in the application. This is a user enumeration vulnerability that affects any Parse Server deployment with email verification enabled (`verifyUserEmails: true`). ### Patches The fix introduces a new Parse Server option `emailVerifySuccessOnInvalidEmail` (default: `true`) that returns a generic success response for all verification email requests, regardless of whether the email address is valid, already verified, or non-existent. This prevents an attacker from distinguishing between these cases. The fix also strengthens the input validation for the related `resetPasswordSuccessOnInvalidEmail` option, and adds security checks that warn when either enumeration mitigation is disabled. ### Workarounds There is no known workaround. ### References - GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-w54v-hf9p-8856 - Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.6.0-alpha.8 - Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.34

CVE-2026-31901 Affected Parse server Versions

2 component(s)
Fixed Versions:
9.6.0-alpha.88.6.34
Product / Package Ecosystem Affected Versions Fixed Version
parse-server
npm/parse-server
npm
≥ 9.0.0-alpha.1
< 9.6.0-alpha.8
9.6.0-alpha.8
parse-server
npm/parse-server
npm
< 8.6.34
8.6.34

References

GitHub Advisory / Wiki ADVISORY
https://github.com/parse-community/parse-server/security/advisories/GHSA-w54v-hf9p-8856
NVD — CVE-2026-31901 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-31901
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/8.6.34
Parse server Release RELEASE
https://github.com/parse-community/parse-server/releases/tag/9.6.0-alpha.8

Frequently Asked Questions

What is CVE-2026-31901?
CVE-2026-31901 is a security vulnerability in Parse server involving Parse Server vulnerable to user enumeration via email verification endpoint under CWE-204: Observable Response Discrepancy.
Which Parse server versions are affected?
Affected versions include releases prior to 9.6.0-alpha.8, 8.6.34 across affected packages: parse-server.
What version fixes CVE-2026-31901?
Upgrading to 9.6.0-alpha.8, 8.6.34 (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.8, 8.6.34. Upgrade your dependency to 9.6.0-alpha.8, 8.6.34 or later.
What CWE is associated with CVE-2026-31901?
CVE-2026-31901 is classified under CWE-204: Observable Response Discrepancy (The product provides different responses to incoming requests in a way that reveals internal state information to an unauthorized actor outside of the intended control sphere.).
How can I check npm dependencies for CVE-2026-31901?
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-w54v-hf9p-8856",
  "modified" : "2026-03-11T21:37:44Z",
  "published" : "2026-03-11T00:36:13Z",
  "aliases" : [ "CVE-2026-31901" ],
  "summary" : "Parse Server vulnerable to user enumeration via email verification endpoint",
  "details" : "### Impact\n\nThe email verification endpoint (`/verificationEmailRequest`) returns distinct error responses depending on whether an email address belongs to an existing user, is already verified, or does not exist. An attacker can send requests with different email addresses and observe the error codes to determine which email addresses are registered in the application.\n\nThis is a user enumeration vulnerability that affects any Parse Server deployment with email verification enabled (`verifyUserEmails: true`).\n\n### Patches\n\nThe fix introduces a new Parse Server option `emailVerifySuccessOnInvalidEmail` (default: `true`) that returns a generic success response for all verification email requests, regardless of whether the email address is valid, already verified, or non-existent. This prevents an attacker from distinguishing between these cases.\n\nThe fix also strengthens the input validation for the related `resetPasswordSuccessOnInvalidEmail` option, and adds security checks that warn when either enumeration mitigation is disabled.\n\n### Workarounds\n\nThere is no known workaround.\n\n### References\n\n- GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-w54v-hf9p-8856\n- Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.6.0-alpha.8\n- Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.34",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "parse-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0-alpha.1"
      }, {
        "fixed" : "9.6.0-alpha.8"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "parse-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "8.6.34"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/security/advisories/GHSA-w54v-hf9p-8856"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-31901"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/parse-community/parse-server"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/releases/tag/8.6.34"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/releases/tag/9.6.0-alpha.8"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-204" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-11T00:36:13Z",
    "nvd_published_at" : "2026-03-11T20:16:16Z"
  }
}