CVE-2026-6441

Canto <= 3.1.1 - Missing Authorization to Authenticated (Subscriber+) Arbitrary Setting Modification

2026-04-16 18:16
Legion Hunter

Strategic Overview

Status
Patched in 3.1.2
Affected Plugin
Canto
Affected Version
<= 3.1.1
CVSS
4.3Medium
Weakness type
CWE-862 · Missing Authorization
CVE
CVE-2026-6441
View all Canto vulnerabilities

At a glance

CVE-2026-6441 is a medium-severity Missing Authorization vulnerability in the Canto WordPress plugin, affecting versions <= 3.1.1. It carries a CVSS score of 4.3 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Subscriber level or above. The issue is fixed in version 3.1.2; sites on affected versions should update now. Disclosed April 2026, reported by Legion Hunter.

Vulnerability Overview

The Canto plugin for WordPress is vulnerable to Missing Authorization in versions up to and including 3.1.1. This is due to the absence of any capability check or nonce verification in the updateOptions() function, which is exposed via two AJAX hooks: wp_ajax_updateOptions (class-canto.php line 231) and wp_ajax_fbc_updateOptions (class-canto-settings.php line 76). Both hooks are registered exclusively under the wp_ajax_ prefix (requiring only a logged-in user), with no call to current_user_can() or check_ajax_referer(). This makes it possible for authenticated attackers with subscriber-level access and above to arbitrarily modify or delete plugin options controlling cron scheduling behavior (fbc_duplicates, fbc_cron, fbc_schedule, fbc_cron_time_day, fbc_cron_time_hour, fbc_cron_start) and to manipulate or clear the plugin's scheduled WordPress cron event (fbc_scheduled_update).

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user.

CWE-862: Missing Authorization

Canto <= 3.1.1 carries this weakness at updateOptions(), and reaching it takes an account at Subscriber level or above. A missing authorization check means a function is reachable by anyone who can reach the endpoint, because the code never asks whether the caller is allowed to perform the action.

Any user who can reach the endpoint gets to run an action reserved for higher-privileged roles, from reading protected data to changing settings or content. For Canto the fix is 3.1.2: builds <= 3.1.1 are affected, anything from 3.1.2 onward is not.

Remediation

Update to version 3.1.2, or a newer patched version

How does WordSec protect against this?

Because it turns on account access, WordSec's login security is the relevant layer: role-based two-factor, captcha and brute-force limits raise the cost of getting the account this needs. None of that substitutes for the fix: Canto 3.1.2 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

Related records

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