The Blue Captcha plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to and including 2.0.1. This is due to missing or incorrect nonce validation on the main admin panel (blcap_main_page) and on the Hall of Shame and Log subpages, which accept a 'blcap_action' / 'action' parameter from $_REQUEST and perform destructive operations (plugin uninstall via blcap_uninstall(), log deletion via blcap_delete_logs(), Hall of Shame deletion via blcap_delete_ip_db(), and adding IPs to the banned list via update_option('blcap_settings')) with no wp_verify_nonce(), check_admin_referer(), or check_ajax_referer() calls anywhere in the codebase. This makes it possible for unauthenticated attackers to uninstall the plugin, delete audit logs, remove Hall of Shame entries, and add arbitrary IP addresses to the block list via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

Quoted source text, attributed separately from HOL analysis.

The Blue Captcha plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to and including 2.0.1. This is due to missing or incorrect nonce validation on the main admin panel (blcap_main_page) and on the Hall of Shame and Log subpages, which accept a 'blcap_action' / 'action' parameter from $_REQUEST and perform destructive operations (plugin uninstall via blcap_uninstall(), log deletion via blcap_delete_logs(), Hall of Shame deletion via blcap_delete_ip_db(), and adding IPs to the banned list via update_option('blcap_settings')) with no wp_verify_nonce(), check_admin_referer(), or check_ajax_referer() calls anywhere in the codebase. This makes it possible for unauthenticated attackers to uninstall the plugin, delete audit logs, remove Hall of Shame entries, and add arbitrary IP addresses to the block list via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

Quoted source text, attributed separately from HOL analysis.