CVE-2026-35200: Parse Server File Upload Content-Type Override Vulnerability

LOW
Advisory Identifier: GHSA-vr5f-2r24-w5hc
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CWE-436
Published
Advisory Summary

CVE-2026-35200 is a LOW file upload content-type override vulnerability (CWE-436: Interpretation Conflict) affecting Parse Server libraries in the npm ecosystem. The issue involves file upload content-type override via extension mismatch. Remediation is available by upgrading affected packages to version 9.7.1-alpha.4, 8.6.73.

CVE-2026-35200 at a Glance

CVE Identifier CVE-2026-35200
GHSA Identifier GHSA-vr5f-2r24-w5hc
Severity LOW
CVSS v3.1 Base Score N/A
CWE Classification CWE-436: Interpretation Conflict
Affected Product Parse Server
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-35200

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: 9.7.1-alpha.4 
npm install parse-server@9.7.1-alpha.4
parse-server fixed: 8.6.73 
npm install parse-server@8.6.73
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-2026-35200, 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 9.7.1-alpha.4), 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-436: Interpretation Conflict, where product a handles inputs or steps differently than product b, which causes a to perform incorrect actions based on its perception of b's state. 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 A file can be uploaded with a filename extension that passes the file extension allowlist (e.g., `.txt`) but with a `Content-Type` header that differs from the extension (e.g., `text/html`). The `Content-Type` is passed to the storage adapter without consistency validation. Storage adapters that store and serve the provided Content-Type (such as S3 or GCS) serve the file with the mismatched Content-Type. The default GridFS adapter is not affected because it derives Content-Type from the filename at serving time. ### Patches The file upload now derives the Content-Type from the filename extension, overriding any user-provided Content-Type when the file has an extension. ### Workarounds Configure the storage adapter or CDN to derive Content-Type from the filename extension instead of using the stored Content-Type.

CVE-2026-35200 Affected Parse Server Versions

2 component(s)
Fixed Versions:
9.7.1-alpha.48.6.73
Product / Package Ecosystem Affected Versions Fixed Version
parse-server
npm/parse-server
npm
≥ 9.0.0
< 9.7.1-alpha.4
9.7.1-alpha.4
parse-server
npm/parse-server
npm
< 8.6.73
8.6.73

References

GitHub Advisory / Wiki ADVISORY
https://github.com/parse-community/parse-server/security/advisories/GHSA-vr5f-2r24-w5hc
NVD — CVE-2026-35200 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-35200
Parse Server Source Repository REPOSITORY
https://github.com/parse-community/parse-server/pull/10383
Parse Server Source Repository REPOSITORY
https://github.com/parse-community/parse-server/pull/10384
Parse Server Source Repository REPOSITORY
https://github.com/parse-community/parse-server

Frequently Asked Questions

What is CVE-2026-35200?
CVE-2026-35200 is a security vulnerability in Parse Server involving File upload Content-Type override via extension mismatch under CWE-436: Interpretation Conflict.
Which Parse Server versions are affected?
Affected versions include releases prior to 9.7.1-alpha.4, 8.6.73 across affected packages: parse-server.
What version fixes CVE-2026-35200?
Upgrading to 9.7.1-alpha.4, 8.6.73 (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 9.7.1-alpha.4, 8.6.73. Upgrade your dependency to 9.7.1-alpha.4, 8.6.73 or later.
What CWE is associated with CVE-2026-35200?
CVE-2026-35200 is classified under CWE-436: Interpretation Conflict (Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B's state.).
How can I check npm dependencies for CVE-2026-35200?
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-vr5f-2r24-w5hc",
  "modified" : "2026-04-06T23:43:26Z",
  "published" : "2026-04-04T04:22:11Z",
  "aliases" : [ "CVE-2026-35200" ],
  "summary" : "Parse Server: File upload Content-Type override via extension mismatch",
  "details" : "### Impact\n\nA file can be uploaded with a filename extension that passes the file extension allowlist (e.g., `.txt`) but with a `Content-Type` header that differs from the extension (e.g., `text/html`). The `Content-Type` is passed to the storage adapter without consistency validation. Storage adapters that store and serve the provided Content-Type (such as S3 or GCS) serve the file with the mismatched Content-Type. The default GridFS adapter is not affected because it derives Content-Type from the filename at serving time.\n\n### Patches\n\nThe file upload now derives the Content-Type from the filename extension, overriding any user-provided Content-Type when the file has an extension.\n\n### Workarounds\n\nConfigure the storage adapter or CDN to derive Content-Type from the filename extension instead of using the stored Content-Type.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "parse-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0"
      }, {
        "fixed" : "9.7.1-alpha.4"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "parse-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "8.6.73"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 8.6.72"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/security/advisories/GHSA-vr5f-2r24-w5hc"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-35200"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/pull/10383"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/parse-community/parse-server/pull/10384"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/parse-community/parse-server"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-436" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-04T04:22:11Z",
    "nvd_published_at" : "2026-04-06T20:16:27Z"
  }
}