The hCaptcha for WordPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's cf7-hcaptcha shortcode in all versions up to, and including, 4.0.0 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

An issue was discovered in the hcaptcha (aka hCaptcha for EXT:form) extension before 2.1.2 for TYPO3. It fails to check that the required captcha field is submitted in the form data. allowing a remote user to bypass the CAPTCHA check.