CVE-2026-87918 in WPBot Plugin
Summary
by MITRE • 09/12/2026
The WPBot WordPress plugin before 8.5.7 does not perform any authorization or nonce check on several AJAX actions that relay prompts to its configured AI providers, allowing unauthenticated attackers to make those third-party API calls, and consume the associated cost, using the site's own configured API keys.
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Analysis
by VulDB Data Team • 09/12/2026
The vulnerability identified in WPBot versions prior to 8.5.7 represents a critical failure in access control mechanisms within the WordPress plugin ecosystem. This flaw specifically affects several AJAX endpoints that are responsible for relaying user prompts to externally configured artificial intelligence providers. In standard web application architecture, AJAX actions handling sensitive operations or those triggering external service calls must implement robust authentication and authorization checks to ensure that only verified users can initiate these processes. However, in this instance, the plugin fails to validate whether the incoming request originates from an authenticated session with appropriate privileges. Furthermore, it neglects to verify nonces, which are unique tokens used to prevent Cross-Site Request Forgery attacks by ensuring that a form submission or AJAX call was genuinely initiated by the user on the site rather than being forged by a malicious actor.
The technical consequence of this oversight is severe because it allows unauthenticated attackers to interact directly with the plugin's API endpoints from any external source, including other websites or automated scripts. Since these endpoints are designed to send prompts to AI providers such as OpenAI or similar services, an attacker can exploit this lack of restriction to force the WordPress site to make numerous API calls on their behalf. The most significant aspect of this exploitation is that the requests utilize the API keys configured within the vulnerable plugin instance. This means the financial burden and potential rate-limiting penalties incurred by these unauthorized queries are borne entirely by the website owner, not the attacker who initiated them.
From an operational perspective, this vulnerability leads to direct financial loss through the consumption of paid AI service quotas or credits associated with the victim's account. Beyond immediate monetary costs, attackers can also induce denial-of-service conditions against the WordPress site itself if they generate a high volume of requests that exhaust server resources or trigger rate limits imposed by the third-party AI provider on behalf of the compromised API key. This could result in temporary suspension of the service for legitimate users until the quota is reset or additional funds are added, effectively disrupting business operations dependent on the plugin's functionality.
This issue aligns with CWE-862, which describes Missing Authorization, as the application does not properly verify that a user has the necessary permissions to perform the action. Additionally, it relates to CWE-352, Cross-Site Request Forgery (CSRF), due to the absence of nonce verification and proper state-changing request protections. In terms of offensive security frameworks, this vulnerability maps to MITRE ATT&CK technique T1078, Valid Accounts, where attackers leverage existing credentials or configurations, although in this specific case, it is more accurately characterized by unauthorized access leading to resource abuse rather than traditional credential theft.
Mitigation for this vulnerability requires immediate action from site administrators and plugin developers. The primary remediation step is to upgrade the WPBot WordPress plugin to version 8.5.7 or later, where these authorization and nonce checks have been implemented. For organizations unable to update immediately due to compatibility concerns, temporary workarounds may include restricting access to the wp-admin directory via IP whitelisting if feasible, although this does not fully mitigate AJAX endpoint exposure unless specific security headers are enforced at the web server level. Long-term prevention involves adhering to secure coding practices that mandate explicit authorization checks and nonce validation for all state-changing or resource-intensive operations within WordPress plugins, ensuring compliance with OWASP guidelines for API security and input validation.