CVE-2026-57661 in WPComplete Plugin
Summary
by MITRE • 06/26/2026
Subscriber Broken Access Control in WPComplete <= 2.9.5.5 versions.
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Analysis
by VulDB Data Team • 06/26/2026
The vulnerability identified as broken access control in WPComplete plugin versions up to 2.9.5.5 represents a critical security flaw that allows unauthorized users to bypass authentication mechanisms and gain elevated privileges within the WordPress environment. This issue falls under the Common Weakness Enumeration category CWE-284 which specifically addresses improper access control vulnerabilities. The flaw enables attackers to manipulate access controls and potentially escalate their privileges from subscriber level to administrator or editor roles, undermining the fundamental security model of the content management system.
The technical implementation of this vulnerability stems from inadequate input validation and insufficient authorization checks within the plugin's core functionality. When users interact with specific endpoints or features within WPComplete, the application fails to properly verify whether the requesting user possesses adequate permissions to perform the requested actions. This weakness manifests particularly when processing requests that should be restricted to authenticated administrators while allowing unauthorized subscribers to execute administrative functions through manipulated parameters or direct API calls.
The operational impact of this vulnerability extends beyond simple privilege escalation as it creates a persistent security risk for WordPress installations using affected plugin versions. Attackers who successfully exploit this flaw can manipulate content, modify user permissions, install malicious plugins, and potentially exfiltrate sensitive data from the compromised website. The vulnerability's exploitation does not require advanced technical skills or specific conditions, making it particularly dangerous in environments where multiple users interact with the system. Security researchers have documented that such access control flaws often serve as initial compromise vectors leading to full system takeover through subsequent attack chains.
Organizations utilizing WPComplete plugin versions prior to 2.9.5.5 face significant risk exposure that requires immediate remediation. The recommended mitigation strategy involves upgrading to the latest plugin version where the access control mechanisms have been properly implemented and validated. Security teams should also implement additional monitoring measures to detect unauthorized access attempts and conduct comprehensive security audits of all installed plugins. The vulnerability aligns with attack patterns described in the MITRE ATT&CK framework under the privilege escalation category, specifically targeting the persistence and privilege escalation techniques that attackers use to maintain long-term access to compromised systems.
System administrators should perform immediate vulnerability assessments across their WordPress installations to identify affected WPComplete versions and ensure proper patch management procedures are in place. The remediation process must include not only updating the vulnerable plugin but also reviewing existing user permissions and implementing principle of least privilege configurations. Organizations should consider implementing web application firewalls and additional access control layers as defensive measures to prevent exploitation attempts, particularly in environments where multiple users with varying permission levels interact with the system. Regular security testing and continuous monitoring of plugin repositories for security advisories will help prevent similar vulnerabilities from being introduced into production environments.