CVE-2026-33538: Parse Server Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-g4cf-xj29-wqqr
Share
CWE-400
Published
Advisory Summary

CVE-2026-33538 is a HIGH denial of service vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Parse Server libraries in the npm ecosystem. The issue involves denial of service via unindexed database query for unconfigured auth providers. Remediation is available by upgrading affected packages to version 9.6.0-alpha.52, 8.6.58.

CVE-2026-33538 at a Glance

CVE Identifier CVE-2026-33538
GHSA Identifier GHSA-g4cf-xj29-wqqr
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Parse Server
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-33538

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.52 
npm install parse-server@9.6.0-alpha.52
parse-server fixed: 8.6.58 
npm install parse-server@8.6.58
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-2026-33538, 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.52), 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-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. 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 cause Denial of Service by sending authentication requests with arbitrary, unconfigured provider names. The server executes a database query for each unconfigured provider before rejecting the request, and since no database index exists for unconfigured providers, each request triggers a full collection scan on the user database. This can be parallelized to saturate database resources. ### Patches The fix validates that an authentication provider is configured before executing any database query. Requests with unconfigured providers are now rejected immediately without querying the database. ### Workarounds There is no known workaround other than upgrading.

CVE-2026-33538 Affected Parse Server Versions

2 component(s)
Fixed Versions:
9.6.0-alpha.528.6.58
Product / Package Ecosystem Affected Versions Fixed Version
parse-server
npm/parse-server
npm
≥ 9.0.0
< 9.6.0-alpha.52
9.6.0-alpha.52
parse-server
npm/parse-server
npm
< 8.6.58
8.6.58

References

GitHub Advisory / Wiki ADVISORY
https://github.com/parse-community/parse-server/security/advisories/GHSA-g4cf-xj29-wqqr
NVD — CVE-2026-33538 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33538
Parse Server Source Repository REPOSITORY
https://github.com/parse-community/parse-server/pull/10270
Parse Server Source Repository REPOSITORY
https://github.com/parse-community/parse-server/pull/10271
Security Fix Commit FIX COMMIT
https://github.com/parse-community/parse-server/commit/40eb442e02672986730007d0a1edb22c1c4bd357
Security Fix Commit FIX COMMIT
https://github.com/parse-community/parse-server/commit/fbac847499e57f243315c5fc7135be1d58bb8e54
Parse Server Source Repository REPOSITORY
https://github.com/parse-community/parse-server

Frequently Asked Questions

What is CVE-2026-33538?
CVE-2026-33538 is a security vulnerability in Parse Server involving Denial of Service via unindexed database query for unconfigured auth providers under CWE-400: Uncontrolled Resource Consumption.
Which Parse Server versions are affected?
Affected versions include releases prior to 9.6.0-alpha.52, 8.6.58 across affected packages: parse-server.
What version fixes CVE-2026-33538?
Upgrading to 9.6.0-alpha.52, 8.6.58 (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.52, 8.6.58. Upgrade your dependency to 9.6.0-alpha.52, 8.6.58 or later.
What CWE is associated with CVE-2026-33538?
CVE-2026-33538 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check npm dependencies for CVE-2026-33538?
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-g4cf-xj29-wqqr",
  "modified" : "2026-03-27T21:53:45Z",
  "published" : "2026-03-24T19:11:40Z",
  "aliases" : [ "CVE-2026-33538" ],
  "summary" : "Parse Server: Denial of Service via unindexed database query for unconfigured auth providers",
  "details" : "### Impact\n\nAn unauthenticated attacker can cause Denial of Service by sending authentication requests with arbitrary, unconfigured provider names. The server executes a database query for each unconfigured provider before rejecting the request, and since no database index exists for unconfigured providers, each request triggers a full collection scan on the user database. This can be parallelized to saturate database resources.\n\n### Patches\n\nThe fix validates that an authentication provider is configured before executing any database query. Requests with unconfigured providers are now rejected immediately without querying the database.\n\n### Workarounds\n\nThere is no known workaround other than upgrading.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
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      "name" : "parse-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0"
      }, {
        "fixed" : "9.6.0-alpha.52"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
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    },
    "ranges" : [ {
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        "introduced" : "0"
      }, {
        "fixed" : "8.6.58"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/security/advisories/GHSA-g4cf-xj29-wqqr"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-33538"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/pull/10270"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/pull/10271"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/commit/40eb442e02672986730007d0a1edb22c1c4bd357"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/commit/fbac847499e57f243315c5fc7135be1d58bb8e54"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/parse-community/parse-server"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-24T19:11:40Z",
    "nvd_published_at" : "2026-03-24T19:16:54Z"
  }
}