CVE-2026-13415 in CMP Plugin
Summary
by MITRE • 08/27/2026
The CMP WordPress plugin before 4.1.18 does not enforce an option-name allow-list when importing settings via one of its AJAX actions, allowing users with the Editor role (when the administrator has granted the Editor role access to the CMP WordPress plugin before 4.1.18's admin-bar controls) to update arbitrary WordPress options, including options that lead to privilege escalation to Administrator.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/27/2026
The vulnerability identified in versions of the Contact Form Manager (CMP) WordPress plugin prior to version 4.1.18 represents a critical failure in input validation and access control mechanisms within the application's administrative interface. Specifically, the flaw resides in one or more AJAX endpoints responsible for importing configuration settings into the WordPress environment. In secure software design, operations that modify system-wide configurations should strictly adhere to an allow-list principle, where only predefined, safe option names are permitted for modification. However, this implementation fails to enforce such a restriction, thereby exposing arbitrary write capabilities to authenticated users who possess elevated but non-administrative privileges.
The technical root cause is a lack of validation on the key parameter used during the import process. When an AJAX request triggers the settings update function, the plugin accepts any string provided as the option name without verifying its existence in a whitelist of permitted configuration keys. This architectural oversight allows attackers to manipulate internal WordPress database entries that are typically protected from lower-privileged users. By exploiting this unrestricted write capability, an attacker can overwrite critical system options such as user roles, capabilities arrays, or authentication salts. The most severe consequence of this flaw is the ability for a user with the Editor role to escalate their privileges to Administrator level. This occurs because WordPress stores user permissions in specific database tables and option fields that, if modified by an unauthorized actor, can grant full control over the website's backend functionality.
From an operational perspective, this vulnerability poses a significant risk to organizations relying on WordPress for content management or e-commerce activities. An attacker with Editor-level access is often considered trusted within many workflows, meaning they may have legitimate reasons to interact with plugin settings. The absence of strict allow-listing means that such interactions can be weaponized without triggering typical anomaly detection systems designed to flag obvious injection attempts from external sources. Once privilege escalation is achieved, the compromised account gains unrestricted access to install malicious plugins, modify theme files, exfiltrate sensitive data, and potentially pivot to compromise other services hosted on the same server infrastructure. This effectively neutralizes the principle of least privilege that WordPress role management aims to enforce.
This vulnerability aligns with CWE-284 Improper Access Control and CWE-915 Improper Extension of Functionality for Arbitrary Code Execution or Privilege Escalation, as it allows a user to extend their functional capabilities beyond what is intended by the system architecture. In terms of the MITRE ATT&CK framework, this behavior corresponds to T1078 Valid Accounts, specifically focusing on privilege escalation through misconfigured permissions and access control mechanisms. The attack vector leverages existing valid credentials rather than exploiting external network vulnerabilities, making it particularly dangerous in environments where internal trust boundaries are weak or poorly defined.
To mitigate this vulnerability, immediate action is required by upgrading the Contact Form Manager plugin to version 4.1.18 or later, which addresses the input validation deficiency. Administrators should also audit user roles within their WordPress installation, ensuring that only necessary users have access to administrative features of third-party plugins. Implementing a Web Application Firewall with rules targeting suspicious AJAX parameter manipulation can provide an additional layer of defense during the transition period. Furthermore, developers and site administrators should adopt strict allow-list validation practices for all configuration import functions in future custom developments or plugin updates to prevent similar logic flaws from recurring. Regular security audits focusing on privilege escalation vectors are recommended to maintain a robust security posture against internal threats.