# Strong Testimonials <= 3.3.12 - Authenticated (Subscriber+) Arbitrary Shortcode Execution via Form Preview

- **ID:** WPSEC-2026-0906
- **Plugin:** Strong Testimonials (`strong-testimonials`), https://wordpress.org/plugins/strong-testimonials/
- **Affected versions:** all versions before 3.3.13
- **Fixed in:** 3.3.13 (Update to 3.3.13 or later.)
- **Severity:** Medium 6.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L)
- **Weakness:** CWE-94
- **Usage among sites WPSec scans:** plugin Medium, affected versions Medium (as of 2026-10-14)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/strong-testimonials
- **Fix released:** 2026-10-13
- **Published:** 2026-10-14
- **URL:** https://wpsec.com/vuln/WPSEC-2026-0906/

## Description

The Strong Testimonials plugin for WordPress is vulnerable to Arbitrary Shortcode Execution via the 'wpmtst_get_form_preview' AJAX action in all versions up to, and including, 3.3.12. This is due to a missing capability check: the handler only verifies the 'wpmtst-admin' nonce, which the plugin prints on every admin page for every logged-in user, and it then renders user-supplied field definitions, passing the 'shortcode_on_form' value to do_shortcode() and an 'action_input' value to do_action(). This makes it possible for authenticated attackers, with Subscriber-level access and above, to execute arbitrary shortcodes and trigger arbitrary action hooks.

## References

- https://wpsec.com/vuln/WPSEC-2026-0906/
- https://plugins.svn.wordpress.org/strong-testimonials/tags/3.3.13/
- https://wordpress.org/plugins/strong-testimonials/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-0906/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.