The Check Plagiarism plugin for WordPress, widely used to detect content duplication, contains a missing authorization vulnerability identified as CVE-2025-11172. The vulnerability stems from the chk_plag_mine_plugin_wpse10500_admin_action() function, which lacks proper capability checks to verify if the authenticated user has sufficient privileges to perform administrative actions. As a result, any authenticated user with at least Subscriber-level access can update the plugin's API key, which is a critical configuration parameter. This unauthorized modification could lead to misuse of the API key, potentially allowing attackers to manipulate plagiarism checking results or cause denial of service by invalidating the key. The vulnerability affects all versions up to and including 2.0 of the plugin. The CVSS v3.1 score of 4.3 reflects a medium severity, with the vector indicating network attack vector, low attack complexity, low privileges required, no user interaction, unchanged scope, no confidentiality impact, limited integrity impact, and no availability impact. No patches have been published yet, and no exploits are known in the wild. The vulnerability is classified under CWE-862 (Missing Authorization).

The primary impact of this vulnerability is the unauthorized modification of the plugin's API key, which compromises the integrity of the plugin's configuration. Attackers with Subscriber-level access can alter the API key, potentially disrupting plagiarism checking services or redirecting API usage to malicious endpoints. While confidentiality and availability remain unaffected, the integrity breach could undermine trust in plagiarism detection results, affecting academic institutions, content publishers, and organizations relying on this plugin for content verification. The ease of exploitation by low-privileged authenticated users increases risk, especially in environments where user accounts are frequently created or compromised. Organizations with large WordPress deployments using this plugin may face operational disruptions and reputational damage if attackers exploit this flaw to manipulate plagiarism reports or disable the plugin’s functionality.

To mitigate this vulnerability, organizations should immediately restrict access to the Check Plagiarism plugin settings to trusted administrators only, ensuring that Subscriber-level users cannot access or invoke administrative actions. Implementing custom capability checks or role-based access controls within WordPress can help enforce this restriction. Monitoring and auditing changes to plugin configurations, especially API key modifications, should be established to detect unauthorized activity promptly. Until an official patch is released, consider temporarily disabling the plugin or limiting its use to trusted users. Additionally, organizations should educate users about the risks of granting unnecessary privileges and enforce strong authentication and account management policies to prevent unauthorized access. Applying web application firewalls (WAFs) with rules targeting suspicious plugin configuration changes can provide an additional layer of defense.