CVE-2026-6441: Auth Bypass (CVSS 4.3)

Description

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).

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CVSS v3.1 Score

4.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS — Exploit Prediction

0.0004

Probability of exploitation

0.11%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-862 Missing Authorization

References

Other References

https://plugins.trac.wordpress.org/browser/canto/tags/3.1.1/includes/class-canto-settings.php#L603 https://plugins.trac.wordpress.org/browser/canto/tags/3.1.1/includes/class-canto.php#L231 https://plugins.trac.wordpress.org/browser/canto/tags/3.1.1/includes/class-canto.php#L572 https://plugins.trac.wordpress.org/browser/canto/trunk/includes/class-canto-settings.php#L603 https://plugins.trac.wordpress.org/browser/canto/trunk/includes/class-canto.php#L231 https://plugins.trac.wordpress.org/browser/canto/trunk/includes/class-canto.php#L572 https://www.wordfence.com/threat-intel/vulnerabilities/id/c1a0200f-9861-4eca-adbf-d458eb6b4e63?source=cve

Frequently Asked Questions

What is CVE-2026-6441? +

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). It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2026-6441? +

CVE-2026-6441 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0004, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-6441? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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