# hCaptcha for WP <= 5.4.1 - Unauthenticated Password Protection Brute Force via REST API 'password' Parameter

- **ID:** WPSEC-2026-2311
- **Plugin:** hCaptcha for WP (`hcaptcha-for-forms-and-more`), https://wordpress.org/plugins/hcaptcha-for-forms-and-more/
- **Affected versions:** all versions before 5.5.0
- **Fixed in:** 5.5.0 (Update to 5.5.0 or later.)
- **Severity:** Medium 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N)
- **Weakness:** CWE-307
- **Usage among sites WPSec scans:** plugin Medium, affected versions Medium (as of 2026-11-03)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/hcaptcha-for-forms-and-more
- **Fix released:** 2026-10-30
- **Published:** 2026-11-03
- **URL:** https://wpsec.com/vuln/WPSEC-2026-2311/

## Description

The hCaptcha for WP plugin for WordPress is vulnerable to a protection mechanism bypass in its password-protected post and page integration in all versions up to, and including, 5.4.1. This is due to the hCaptcha challenge being enforced only on the post password form (wp-login.php?action=postpass), while the WordPress REST API posts and comments endpoints accept a 'password' parameter and check it without any CAPTCHA. This makes it possible for unauthenticated attackers to brute-force the passwords of password-protected posts and pages without solving the hCaptcha challenge, and to read their content once a password is guessed.

## References

- https://wpsec.com/vuln/WPSEC-2026-2311/
- https://plugins.svn.wordpress.org/hcaptcha-for-forms-and-more/tags/5.5.0/
- https://wordpress.org/plugins/hcaptcha-for-forms-and-more/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-2311/

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.