CVE intelligence and bounded remediation

CVE-2026-3335 — Canto security vulnerability

Medium CVSS 5.3

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.

Severity
Medium
CVSS
5.3 (3.1)
Published
2026-03-21
CISA KEV
Not currently listed
Ecosystem
php/wordpress
Weaknesses
CWE-862

Affected products

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Matched remediation archetype

Authorization bypass, IDOR, and cross-tenant access

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Check exposure

  • Map object and action authorization checks across API, UI, batch, import/export, and background-job paths.
  • Identify tenant, ownership, role, and policy boundaries for affected resources and administrative operations.
  • Use synthetic fixtures to compare intended access matrices without accessing another user's real data.

Remediate safely

  • Enforce server-side authorization at each resource access and state transition using the authenticated principal and trusted tenant context.
  • Scope data queries by tenant and ownership; treat client-supplied identifiers, roles, and policy claims as untrusted.
  • Add deny-by-default policy tests for horizontal and vertical access across every affected transport.

Authoritative sources

Complete CVE record and remediation plan

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