Blue Captcha <= 2.0.1 - Cross-Site Request Forgery via 'blcap_action' Parameter
Strategic Overview
- Status
- Unpatched
- Affected Plugin
- Blue Captcha
- Affected Version
<= 2.0.1- CVSS
- 4.3Medium
- Weakness type
- CWE-352 · Cross-Site Request Forgery (CSRF)
- CVE
CVE-2026-10552
At a glance
CVE-2026-10552 is a medium-severity Cross-Site Request Forgery (CSRF) vulnerability in the Blue Captcha WordPress plugin, affecting versions <= 2.0.1. It carries a CVSS score of 4.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. No fixed release has been reported yet; treat installations running this software as exposed. Disclosed June 2026, reported by Kamil Królikowski.
Vulnerability Overview
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.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site.
CWE-352: Cross-Site Request Forgery (CSRF)
Blue Captcha <= 2.0.1 carries this weakness at blcap_action, and reaching it takes a caller who can reach the endpoint. Cross-site request forgery abuses the fact that browsers attach a victim's cookies to any request, so a state-changing action that only checks who you are, not whether you meant to act, can be triggered from another site.
An attacker who gets a logged-in user to load a crafted page can perform that action as them, with the impact scaling to whatever the victim's role is allowed to do. No fixed build of this plugin is recorded for Blue Captcha yet, so installs running <= 2.0.1 stay exposed until the vendor ships one.
Remediation
No known patch available. Please review the vulnerability's details in depth and employ mitigations based on your organization's risk tolerance. It may be best to uninstall the affected software and find a replacement.
How does WordSec protect against this?
The attempt arrives as an ordinary request to Blue Captcha: WordSec's web application firewall inspects request payloads before WordPress loads them. No patched version is recorded yet, which is the case where a filtering layer matters most, because there is nothing to update to.
- Firewall
- Alerts
External References
Related records
Other vulnerabilities in Blue Captcha
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