Is CVE-2026-35200 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-35200 being exploited in the wild.

How severe is CVE-2026-35200?

Medium severity, with a CVSS score of 5.4, published 6 April 2026.

Which products and versions are affected?

parse-server (npm) SEMVER:introduced=9.0.0,fixed=9.7.1-alpha.4.

Is there a fix for CVE-2026-35200?

Yes. parse-server (npm): upgrade to 9.7.1-alpha.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-35200 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-35200?

Check whether you run parse-server (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-35200: Parse Server stored XSS via Content-Type mismatch in file uploads

CVE-2026-35200 · Severity: medium · CVSS 5.4 · Published 2026-04-06

Parse Server, an open-source backend for Node.js applications, contains a vulnerability in how it handles file uploads. An attacker can upload a file that appears harmless (like a text file) but is actually treated as a malicious web page (HTML) by the storage system. This could allow an attacker to perform cross-site scripting (XSS) attacks, potentially leading to the theft of user session data or unauthorized actions on the platform.

Technologies: parse-server (npm). Vendors: npm.

Quick answers

Is CVE-2026-35200 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-35200 being exploited in the wild.
How severe is CVE-2026-35200?: Medium severity, with a CVSS score of 5.4, published 6 April 2026.
Which products and versions are affected?: parse-server (npm) SEMVER:introduced=9.0.0,fixed=9.7.1-alpha.4.
Is there a fix for CVE-2026-35200?: Yes. parse-server (npm): upgrade to 9.7.1-alpha.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-35200 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-35200?: Check whether you run parse-server (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

parse-server (npm): upgrade to 9.7.1-alpha.4 or later
```
npm install parse-server@9.7.1-alpha.4
```

Technical details

A vulnerability exists in Parse Server's FilesController where the 'Content-Type' header provided during a file upload is not validated against the file's extension. An attacker with upload privileges can bypass extension allowlists by providing a permitted extension (e.g., .txt) while specifying a different MIME type (e.g., text/html) in the header. When using storage adapters that rely on the stored metadata to serve files (such as Amazon S3 or Google Cloud Storage), the file is served with the attacker-controlled MIME type, enabling stored XSS. The default GridFS adapter is unaffected as it derives MIME types from filenames at request time. The fix ensures the Content-Type is derived from the file extension, overriding user-provided headers.

Affected products

Parse Platform Parse Server < 8.6.73, >= 9.0.0 < 9.7.1-alpha.4

Identifiers

CVE-2026-35200
GHSA-vr5f-2r24-w5hc

Timeline

2026-04-02: patched: Fixes merged in PR #10383 and #10384
2026-04-06: disclosed: Initial advisory published
2026-04-06: advisory: NVD published CVE-2026-35200

References

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