CVE-2026-35200

Description

### 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.

How to fix CVE-2026-35200

To remediate CVE-2026-35200, upgrade the affected package to a fixed version below.

• —upgrade to 8.6.73 or later
• —upgrade to 9.7.1-alpha.4 or later

Is CVE-2026-35200 being exploited?

Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 8.6.73, >= 9.0.0, < 9.7.1
• >= 9.0.0, < 9.7.1-alpha.4

CVSS scores

References (5)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2026-35200
• PATCHgithub.com/parse-community/parse-server
• WEBgithub.com/parse-community/parse-server/pull/10383
• WEBgithub.com/parse-community/parse-server/pull/10384