# ClickCease Click Fraud Protection <= 3.3.0 - Unauthenticated Missing Authorization to Server-Side Protection Bypass via validate_clickcease_response AJAX Action

- **ID:** WPSEC-2026-2253
- **Plugin:** ClickCease Click Fraud Protection (`clickcease-click-fraud-protection`), https://wordpress.org/plugins/clickcease-click-fraud-protection/
- **Affected versions:** all versions before 3.3.1
- **Fixed in:** 3.3.1 (Update to 3.3.1 or later.)
- **Severity:** Medium 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N)
- **Weakness:** CWE-862
- **Usage among sites WPSec scans:** plugin Low, affected versions Low (as of 2026-11-03)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/clickcease-click-fraud-protection
- **Fix released:** 2026-11-01
- **Published:** 2026-11-03
- **URL:** https://wpsec.com/vuln/WPSEC-2026-2253/

## Description

The ClickCease Click Fraud Protection plugin for WordPress is vulnerable to unauthorized modification of data via the public validate_clickcease_response AJAX action in all versions up to, and including, 3.3.0. This is due to the RTI_Service::validateRTIClient() function updating the 'cheq_invalid_secret' site option based on the result of decrypting an attacker-supplied 'cheq_hash' value, while the required nonce is exposed to every front-end visitor. This makes it possible for unauthenticated attackers to send a malformed hash that sets the flag and disables the plugin's server-side bot and click-fraud validation site-wide.

## References

- https://wpsec.com/vuln/WPSEC-2026-2253/
- https://plugins.svn.wordpress.org/clickcease-click-fraud-protection/tags/3.3.1/
- https://wordpress.org/plugins/clickcease-click-fraud-protection/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-2253/

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.