Vulnerability · Published Mar 21, 2026 · Assigned by Wordfence
CVE-2026-3335Canto <= 3.1.1 - Missing Authorization to Unauthenticated File Upload
Medium 5.3
In plain English
A medium-severity missing authorization in Canto from flightbycanto. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 67% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei.
Official description
The Canto plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 3.1.1 via the `/wp-content/plugins/canto/includes/lib/copy-media.php` file. This is due to the file being directly accessible without any authentication, authorization, or nonce checks, and the `fbc_flight_domain` and `fbc_app_api` URL components being accepted as user-supplied POST parameters rather than read from admin-configured options. Since the attacker controls both the destination server and the `fbc_app_token` value, the entire fetch-and-upload chain is attacker-controlled — the server never contacts Canto's legitimate API, and the uploaded file originates entirely from the attacker's infrastructure. This makes it possible for unauthenticated attackers to upload arbitrary files (constrained to WordPress-allowed MIME types) to the WordPress uploads directory. Additional endpoints (`detail.php`, `download.php`, `get.php`, `tree.php`) are also directly accessible without authentication and make requests using a user-supplied `app_api` parameter combined with an admin-configured subdomain.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| flightbycanto | Canto | 0 – through 3.1.1 |
Weakness: CWE-862 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
References
- https://www.wordfence.com/threat-intel/vulnerabilities/id/0777f759-6980-4572-a866-0210bd5f5085?source=cve
- https://plugins.trac.wordpress.org/browser/canto/tags/3.1.1/includes/lib/copy-media.php#L71
- https://plugins.trac.wordpress.org/browser/canto/tags/3.1.1/includes/lib/copy-media.php#L152
- https://plugins.trac.wordpress.org/browser/canto/trunk/includes/lib/copy-media.php#L71
- https://plugins.trac.wordpress.org/browser/canto/trunk/includes/lib/copy-media.php#L152
- https://plugins.trac.wordpress.org/browser/canto/tags/3.1.1/includes/lib/copy-media.php#L306
- https://plugins.trac.wordpress.org/browser/canto/trunk/includes/lib/copy-media.php#L306