Cloudinary unsigned presets are public upload endpoints; harden them

TL;DR

Treat an unsigned preset as a public upload endpoint: lock it down with allowed formats, a max file size, a fixed folder, and unique filenames. For anything sensitive, switch to signed server-side uploads with access_mode authenticated and short-lived signed delivery URLs instead.

Steps

1. Treat an unsigned preset as a public upload endpoint: lock it down with allowed formats, a max file size, a fixed folder, and unique filenames. For anything sensitive, switch to signed server-side uploads with access_mode authenticated and short-lived signed delivery URLs instead. Review existing presets for unrestricted unsigned ones before launch.

When to use

You are seeing this: Review existing presets for unrestricted unsigned ones before launch. Use this skill when you run into "Cloudinary unsigned presets are public upload endpoints; harden them".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Source: Web (project setup guide, Cloudinary upload preset notes): an unsigned upload preset bakes the cloud name and preset name into the public JavaScript bundle, so anyone can upload arbitrary files into the Cloudinary account, and every uploaded file is served from a public CDN URL with no access control. The guide warns against pointing an unsigned preset at an account holding sensitive documents. Browser uploads need the preset to be unsigned, which makes hardening the preset itself the only guardrail.

Verified resolution: Treat an unsigned preset as a public upload endpoint: lock it down with allowed formats, a max file size, a fixed folder, and unique filenames. For anything sensitive, switch to signed server-side uploads with access_mode authenticated and short-lived signed delivery URLs instead. Review existing presets for unrestricted unsigned ones before launch.

Source URL: https://github.com/ayushr27/placement-portal/blob/HEAD/website/CREATEUPLOADPRESET.md