Simple CAPTCHA with Cloudflare Turnstile <= 1.43.2 - Unauthenticated CAPTCHA Bypass via FluentAuth Compatibility 'action' Parameter
- ID
- WPSEC-2026-0262
- Plugin
- Simple CAPTCHA with Cloudflare Turnstile (simple-cloudflare-turnstile)
- Affected
- from 1.42.0 before 1.44.0
- Remediation
- Update to 1.44.0 or later.
- CVSS 3.1
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- Weakness
- CWE-288
- Usage
- Plugin Medium · Affected versions Medium among sites WPSec scans, 2026-10-22
- Attack surface
- Simple CAPTCHA with Cloudflare Turnstile on WPSec AttackSurface
- Fix released
- Published
Description
The Simple CAPTCHA with Cloudflare Turnstile plugin for WordPress is vulnerable to a CAPTCHA bypass in versions 1.42.0 up to, and including, 1.43.2. This is due to its FluentAuth compatibility code skipping the Turnstile login check for any admin-ajax request carrying action=fluent_auth_2fa_email, without confirming that the request was an already-verified FluentAuth two-factor login. Because login forms such as WooCommerce's are also processed on admin-ajax requests, unauthenticated attackers can add this parameter to a credential submission and skip the Turnstile check on password logins, enabling automated credential brute-force attacks against any account. Exploitation requires the FluentAuth (Fluent Security) plugin to be active and the plugin's WordPress login protection to be enabled.
References
- https://wpsec.com/vuln/WPSEC-2026-0262/
- https://plugins.svn.wordpress.org/simple-cloudflare-turnstile/tags/1.44.0/
- https://wordpress.org/plugins/simple-cloudflare-turnstile/
Published by WPSec. Provided as is, without warranty. Corrections: contact us.
This advisory as JSON or Markdown · All advisories: JSON, RSS