CVE-2026-22400 is a medium-severity authorization bypass vulnerability identified in Mikado-Themes Holmes, a WordPress theme product widely used for website development. The vulnerability stems from an incorrectly configured access control mechanism that relies on user-controlled keys to determine authorization levels. Specifically, the theme's security model allows an attacker with limited privileges (PR:L) to manipulate keys or parameters that control access rights, thereby bypassing intended restrictions and gaining unauthorized access to protected resources or functionalities. The vulnerability affects all versions of Holmes up to and including 1.7. The CVSS 3.1 vector (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N) indicates that the attack can be performed remotely over the network with low attack complexity, requires some privileges but no user interaction, and impacts confidentiality and integrity but not availability. No public exploits or patches have been reported yet, but the issue is published and recognized by the CVE database. The root cause is a misconfiguration in access control logic, which is a common weakness in web applications, especially themes or plugins that implement custom authorization schemes. Attackers exploiting this vulnerability could access or modify data they should not be authorized to, potentially leading to data leakage or unauthorized content changes on affected websites.

For European organizations, the impact of CVE-2026-22400 depends largely on the extent of Mikado-Themes Holmes usage within their web infrastructure. Organizations using this theme for corporate websites, e-commerce, or client portals could face unauthorized access to sensitive information or unauthorized content modifications. This could lead to reputational damage, data privacy violations under GDPR, and potential compliance issues. Since the vulnerability affects confidentiality and integrity but not availability, the primary risks are data leakage and unauthorized data manipulation rather than service disruption. Attackers with limited privileges could escalate their access, potentially compromising user data or administrative functions. Given the medium severity and ease of remote exploitation without user interaction, the threat is significant enough to warrant prompt attention, especially for sectors handling sensitive customer or business data such as finance, healthcare, and government services in Europe.

European organizations should immediately audit their use of Mikado-Themes Holmes and identify any installations running version 1.7 or earlier. Until an official patch is released, administrators should review and tighten access control configurations within the theme settings, ensuring that user-controlled keys or parameters cannot influence authorization decisions. Employing web application firewalls (WAFs) to detect and block suspicious requests that attempt to manipulate authorization keys can provide temporary protection. Organizations should also monitor logs for unusual access patterns indicative of privilege escalation attempts. Regularly updating all WordPress themes and plugins to their latest versions is critical once patches become available. Additionally, implementing the principle of least privilege for user accounts and restricting administrative access can reduce the risk of exploitation. Security teams should prepare incident response plans tailored to web application compromises involving unauthorized access or data modification.