CVE-2026-66464 in Internal Link Optimiser Plugin
Summary
by MITRE • 08/13/2026
Unauthenticated Broken Access Control in Internal Link Optimiser <= 5.2.7 versions.
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Analysis
by VulDB Data Team • 08/13/2026
This vulnerability represents a critical broken access control flaw that affects the Internal Link Optimiser plugin for WordPress systems. The issue stems from insufficient authentication checks within the plugin's administrative functions, allowing any unauthenticated user to exploit administrative capabilities. The vulnerability is classified under CWE-284 which specifically addresses improper access control mechanisms in software applications. Attackers can leverage this weakness to perform unauthorized operations that should only be available to authenticated administrators, potentially leading to complete system compromise.
The technical implementation of this flaw involves the plugin's failure to properly validate user authentication status before executing privileged actions. When users attempt to access certain administrative endpoints within the Internal Link Optimiser plugin, the application does not verify whether the requesting user possesses appropriate authorization levels. This oversight creates a pathway for malicious actors to manipulate the application's behavior through crafted requests that bypass normal access controls. The vulnerability affects all versions up to and including 5.2.7, indicating this was a persistent issue within the plugin's codebase that remained unresolved for an extended period.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass complete system compromise potential. An unauthenticated attacker could exploit this weakness to modify internal link configurations, potentially redirecting traffic to malicious destinations or disrupting legitimate navigation patterns. The compromised plugin functionality might allow attackers to inject malicious code into the WordPress installation, especially if the plugin's administrative interface provides database modification capabilities. This type of vulnerability aligns with ATT&CK technique T1078 which covers valid accounts and credential manipulation as part of broader attack chains.
Security professionals should immediately implement mitigations including updating to the latest version of the Internal Link Optimiser plugin where this vulnerability has been addressed. If immediate updates are not possible, administrators should consider implementing additional access controls such as IP whitelisting for administrative endpoints or deploying web application firewalls that can detect and block exploitation attempts. The vulnerability demonstrates how seemingly minor access control oversights can create significant security risks, emphasizing the importance of proper authentication validation in all application components. Organizations should also conduct thorough audits of their WordPress installations to identify other plugins that might contain similar access control weaknesses. This particular vulnerability serves as a reminder of the critical need for comprehensive security testing and regular updates to maintain robust protection against unauthorized access attempts.
The presence of this unauthenticated access control failure highlights the importance of proper input validation and authentication checks in web applications, particularly those handling administrative functions. Security practitioners should ensure that all user actions requiring elevated privileges are properly authenticated before execution, following established security frameworks such as those defined by the Open Web Application Security Project. This vulnerability type represents a fundamental flaw in application security architecture that can be exploited across various platforms where proper access control mechanisms are not implemented or maintained correctly.