Medium

Canto <= 3.1.1 - Missing Authorization to Unauthenticated File Upload

  • Disclosed: 20.03.2026
  • Updated: 11.10.2026 10:22

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 software

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PlatformPackageVulnerable versionsFixed in
WordPress plugin Canto <= 3.1.1 3.1.2

References

CVSS score 5.3/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness (CWE)
CWE-862
Platform
WordPress
Package
Canto
Disclosed
20.03.2026
Updated
11.10.2026 10:22

Sources and licenses

Wordfence Intelligence - 0777f759-6980-4572-a866-0210bd5f5085 - Wordfence Intelligence

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Copyright 2012-2026 Defiant Inc.

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Copyright 2012-2026 Defiant Inc.

Defiant hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute this software vulnerability information. Any copy of the software vulnerability information you make for such purposes is authorized provided that you include a hyperlink to this vulnerability record and reproduce Defiant's copyright designation and this license in any such copy.

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Wordfence Intelligence
Wordfence Intelligence - Defiant, Inc.
Copyright Defiant, Inc. All rights reserved except as granted below.
License grant, section 3.1 of the Wordfence Intelligence Terms and Conditions (January 26, 2026):

Subject to this Agreement, Company hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute the Service. Any copy you make for such purposes is authorized provided that you reproduce Company’s copyright designation, this license, and the license of any disclosed Company licensor in any such copy.

Full applicable Agreement: https://www.wordfence.com/wordfence-intelligence-terms-and-conditions/

Vulnerability history: Canto

All published vulnerabilities of this package (WordPress plugin), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (9) in the archive
Total entries
9
First → latest
03.2020 04.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • Critical 3
  • High 4
  • Medium 2

Disclosures per year

  1. 2020: 4
  2. 2021: 0
  3. 2022: 0
  4. 2023: 1
  5. 2024: 2
  6. 2025: 0
  7. 2026: 2
Severity:
  1. Canto <= 3.1.1 - Missing Authorization to Unauthenticated File Upload this entry
    Medium · 5.3 CVE-2026-3335 <= 3.1.1 3.1.2
  2. Critical · 9.8 CVE-2024-4936 <= 3.0.8 3.0.9
  3. Critical · 9.8 CVE-2024-25096 <= 3.0.6 3.0.7
  4. Critical · 9.8 CVE-2023-3452 <= 3.0.4 3.0.5
  5. High · 8.3 CVE-2020-28976 <= 1.9.0 2.0.1
  6. High · 8.3 CVE-2020-28978 < 2.0.1 2.0.1
  7. High · 8.3 CVE-2020-28977 <= 1.9.0 2.0.1

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