Arbitrary file upload in Parse Server - #VU135973
Published: June 30, 2026
Vulnerability identifier: #VU135973
CSH Severity: Low
CVSS v4: 4.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-434
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to execute arbitrary script in other users' browsers.
The vulnerability exists due to unrestricted upload of file with dangerous type in the file upload validation and storage handling when uploading a file with an unrecognized extension and a malformed Content-Type. A remote user can upload a crafted file whose body begins with HTML markup to execute arbitrary script in other users' browsers.
Exploitation requires permission to upload files and affects storage adapters that persist and serve the uploaded Content-Type, while the default GridFS storage adapter is not affected.
Affected software
Parse Server
Remediation
Install security update from vendor's website.
Parse Server - addressed in versions 8.6.84, 9.10.0 alpha.2