CVE-2026-111965 in Profile Builder Plugin
Summary
by MITRE • 10/23/2026
The Profile Builder WordPress plugin from 4.0.0 to 4.0.4 does not enforce its reCAPTCHA verification on all comment submission paths, allowing authenticated users to bypass the anti-spam protection an administrator configured for the WordPress comment form.
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Analysis
by VulDB Data Team • 10/23/2026
Profile Builder is a widely utilized WordPress plugin designed to manage user registration, login, and profile editing functionalities within WordPress environments. Versions 4.0.0 through 4.0.4 contain a critical logic flaw in how anti-spam protections are applied to the comment submission process. Specifically, while administrators can configure reCAPTCHA verification for standard comments posted via the default WordPress interface, this security control is not consistently enforced across all code paths that handle comment submissions initiated by authenticated users. This inconsistency creates a significant gap in the defense-in-depth strategy employed by many site owners who rely on these plugins to mitigate automated abuse and spam attacks.
The technical root of this vulnerability lies in an incomplete implementation of input validation logic within the plugin's backend processing routines. When an unauthenticated user submits a comment through the standard form, the plugin correctly intercepts the request and validates the reCAPTCHA token before allowing the submission to proceed. However, when an authenticated user attempts to post a comment, particularly through alternative endpoints or AJAX-based submission methods that are often used for dynamic content updates or mobile applications interacting with the WordPress REST API, the validation step is bypassed entirely. The code fails to check for the presence of a valid reCAPTCHA response in these specific execution paths, effectively treating authenticated users as trusted entities without verifying their humanity status against Google's anti-bot service. This oversight allows any user who has successfully logged into the site to submit comments without undergoing the intended spam protection checks.
The operational impact of this vulnerability is substantial for website administrators and owners relying on automated moderation tools. By bypassing reCAPTCHA, attackers can leverage compromised or low-privilege accounts to flood comment sections with malicious content, including phishing links, malware distribution URLs, or SEO-spamming keywords designed to manipulate search engine rankings. Because the user is authenticated, these comments may also carry more weight in certain community-driven sites where reputation systems are tied to account activity. Furthermore, this flaw facilitates automated scripting attacks against the site's comment infrastructure, as scripts can easily authenticate and submit spam without needing to solve CAPTCHAs or interact with complex browser-based challenges. This undermines the integrity of user-generated content and increases the administrative burden required for manual moderation and cleanup efforts.
From a classification perspective, this issue aligns closely with CWE-284 Improper Access Control, as it involves an authorization bypass where security controls are not uniformly applied across all access vectors. It also relates to CWE-798 Use of Hard-coded Credentials if the authentication mechanism itself is weak, but primarily reflects CWE-601 URL Redirection to Untrusted Site in terms of potential downstream attacks via malicious links posted through this vector. In the context of the MITRE ATT&CK framework for enterprise security, this vulnerability supports techniques associated with Initial Access and Execution by allowing adversaries to establish a foothold or maintain persistence through spam campaigns that are harder to detect due to their origin from legitimate user accounts.
To mitigate this risk, administrators should immediately update the Profile Builder plugin to version 4.0.5 or later, where the developers have patched these logic gaps to ensure reCAPTCHA verification is enforced consistently across all comment submission paths regardless of user authentication status. Until an upgrade can be performed, site owners may consider implementing additional server-side rules using a Web Application Firewall (WAF) to monitor and rate-limit comment submissions from authenticated users who exhibit suspicious behavior patterns. Additionally, enabling strict CAPTCHA policies at the web server level or utilizing third-party security plugins that enforce global anti-spam measures can provide an overlapping layer of protection. Regular auditing of plugin code for similar inconsistencies in other forms is also recommended to prevent analogous vulnerabilities in registration or profile update processes.