CVE-2026-111396 in Advanced Post Manager Plugin
Summary
by MITRE • 10/16/2026
Missing Authorization vulnerability in Liquid Web / StellarWP Advanced Post Manager advanced-post-manager allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects Advanced Post Manager: from n/a through 4.5.6.
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Analysis
by VulDB Data Team • 10/16/2026
The identified security flaw resides within the Advanced Post Manager plugin, specifically affecting versions ranging from initial releases up to version 4.5.6 distributed by Liquid Web and StellarWP. This vulnerability is classified as a missing authorization issue, which fundamentally represents an incorrect implementation of access control mechanisms designed to restrict user actions based on their assigned roles or permissions. In typical WordPress environments, administrative functions such as managing posts, pages, media, and custom post types are strictly gated behind authentication checks that verify whether the current user possesses sufficient privileges to perform the requested action. However, in this specific instance, these security levels were incorrectly configured, allowing unauthenticated users or those with lower privilege levels to bypass intended restrictions and execute administrative operations without proper verification of their authority.
From a technical perspective, the root cause lies in the failure of the application logic to enforce server-side authorization checks before processing requests related to post management tasks. While client-side controls might visually hide certain menu items from users who lack permission, these are easily bypassed by directly interacting with the underlying API endpoints or form submissions associated with those features. The vulnerability allows an attacker to manipulate HTTP requests to perform actions such as creating, editing, deleting, or publishing content on behalf of administrators. This type of flaw is commonly categorized under CWE-269, which denotes Improper Privilege Control, indicating that the software does not properly assign privileged functions to authorized actors. Furthermore, this behavior aligns with ATT&CK technique T1078, Valid Accounts, as it enables an attacker to leverage existing but insufficiently secured credentials or even anonymous access to gain unauthorized control over critical site functionalities.
The operational impact of this vulnerability is significant for any WordPress installation running the affected versions of Advanced Post Manager. An attacker can exploit this misconfiguration to deface websites by altering content, inject malicious scripts through post bodies that execute when viewed by legitimate users, or delete essential data leading to service disruption. In more severe scenarios, if combined with other vulnerabilities such as cross-site scripting or SQL injection within the same plugin, the impact could escalate to full server compromise. The ability to manipulate posts without authorization undermines the integrity of the content management system and can lead to reputational damage for site owners who rely on these platforms for their digital presence. It also poses a risk to user privacy if sensitive information stored in custom post types is exposed or altered by unauthorized parties.
To mitigate this vulnerability, immediate action is required to update the Advanced Post Manager plugin to version 4.5.7 or later, where the authorization checks have been properly implemented and tested. Site administrators should verify that no older versions remain active on their servers, as even if a primary theme uses an updated version of the plugin, other plugins might still rely on vulnerable copies. Additionally, implementing Web Application Firewall rules can provide a layer of defense by blocking suspicious request patterns associated with privilege escalation attempts. Regular security audits and penetration testing are recommended to identify similar misconfigurations in custom code or third-party extensions that may not have received automatic updates. Maintaining strict adherence to the principle of least privilege ensures that only necessary permissions are granted, reducing the attack surface available to potential adversaries seeking to exploit access control weaknesses.