CVE-2026-28567 in WP Sort Order Plugin
Summary
by MITRE • 08/18/2026
Unauthenticated Broken Access Control in WP Sort Order <= 1.3.5 versions.
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Analysis
by VulDB Data Team • 08/18/2026
The vulnerability identified as an unbroken access control issue within the WordPress plugin WP Sort Order, specifically affecting versions up to and including 1.3.5, represents a critical failure in server-side authorization mechanisms. This flaw allows any user, regardless of their authentication status or role level, to perform administrative actions that should be strictly restricted to users with elevated privileges such as administrators. In the context of web application security, this is classified under CWE-284 Improper Access Control and aligns with MITRE ATT&CK technique T1078 Valid Accounts when exploited by authenticated low-level users or T1505 Server Software Component if it involves plugin manipulation. The core technical deficiency lies in the absence of capability checks within the PHP code handling user interface requests, meaning that critical functions are exposed via public-facing endpoints without verifying whether the requester possesses the necessary permissions to execute them.
From a technical perspective, this vulnerability typically manifests through insecure direct object references or missing function-level access controls where the application relies solely on client-side restrictions or assumes that only logged-in users will attempt to modify settings. In WordPress environments, plugins often register AJAX handlers or REST API endpoints without adequately validating current user capabilities using functions such as current_user_can(). When these checks are omitted or incorrectly implemented, an attacker can craft specific HTTP requests to trigger administrative operations directly. This could include modifying site-wide configuration options, altering database structures related to post sorting mechanisms, or injecting malicious code into plugin settings that persist across sessions. The lack of nonce verification further exacerbates the risk by allowing Cross-Site Request Forgery attacks where a victim user might be tricked into executing these actions unintentionally if they are logged in with higher privileges.
The operational impact of this vulnerability is severe due to its potential for complete site compromise and data integrity loss. An unauthenticated attacker can exploit this flaw to gain unauthorized administrative access, effectively bypassing the authentication layer entirely or escalating privileges from a low-level subscriber account to full administrator status if combined with other vectors like credential stuffing. Once inside, the attacker can deface the website by altering content displayed to visitors, steal sensitive data stored in WordPress options tables such as API keys and database credentials, or install additional malicious plugins that serve as backdoors for persistent access. This leads directly to confidentiality breaches of user information and integrity violations where legitimate site modifications are overwritten with malicious intent. Furthermore, it undermines the trust model of the CMS ecosystem by allowing arbitrary code execution contexts if the plugin settings allow HTML or script injection without proper sanitization.
Mitigation strategies must focus on immediate remediation through software updates and rigorous security hardening practices. The primary defense is to upgrade WP Sort Order to version 1.3.6 or later, where developers have presumably implemented robust capability checks ensuring that only users with the manage_options capability can access sensitive endpoints. For sites unable to update immediately due to compatibility constraints, temporary mitigations include restricting plugin file permissions via web server configuration such as Apache mod_authz_core or Nginx deny rules to block direct execution of vulnerable PHP files from untrusted sources. Additionally, implementing a Web Application Firewall with rules targeting known exploitation patterns for this specific vulnerability can provide an external layer of defense by inspecting request payloads and blocking suspicious POST requests that attempt to modify plugin settings without valid nonces. Regular security audits focusing on access control logic in custom code are essential to prevent similar flaws from being introduced during future development cycles, ensuring adherence to OWASP Top 10 guidelines regarding broken access control vulnerabilities.