CVE-2025-14540 in Userback Plugin
Summary
by MITRE • 12/13/2025
The Userback plugin for WordPress is vulnerable to unauthorized access of data due to a missing capability check on the userback_get_json function in all versions up to, and including, 1.0.15. This makes it possible for authenticated attackers, with Subscriber-level access and above, to extract plugin's configuration data including the Userback API access token and site's posts/pages contents, including those that have private and draft status.
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Analysis
by VulDB Data Team • 12/13/2025
The vulnerability identified as CVE-2025-14540 affects the Userback plugin for WordPress, representing a critical authorization flaw that undermines the security posture of affected installations. This issue stems from a fundamental missing capability check within the userback_get_json function, which operates across all versions up to and including 1.0.15. The flaw creates a pathway for authenticated attackers who possess at least Subscriber-level privileges to bypass intended access controls and extract sensitive configuration data from the plugin. This represents a significant escalation of privilege vulnerability where low-privilege users can gain access to data that should remain restricted to administrators or higher-level users.
The technical implementation of this vulnerability resides in the absence of proper capability verification within the userback_get_json function, which is designed to handle data retrieval operations. According to CWE-284, this constitutes an improper access control mechanism where the system fails to properly validate user permissions before granting access to sensitive resources. The function should require administrator-level privileges or specific capabilities to access plugin configuration data, but instead operates without adequate authorization checks. This misconfiguration allows attackers to exploit the function through legitimate plugin interfaces, making the attack vector both straightforward and difficult to detect.
The operational impact of this vulnerability extends beyond simple data exposure, as it provides attackers with access to comprehensive site content including private and draft posts and pages. The extraction of Userback API access tokens represents a particularly dangerous aspect of this vulnerability, as these tokens could potentially be used to access external services or APIs that the plugin integrates with, expanding the attack surface beyond the WordPress installation itself. The ability to access draft and private content creates opportunities for information disclosure that could include sensitive business data, unpublished content, or confidential communications that should remain protected. This vulnerability directly violates the principle of least privilege and demonstrates inadequate input validation and access control mechanisms within the plugin's architecture.
Security professionals should consider this vulnerability in the context of the ATT&CK framework, specifically under the T1213.002 technique related to data from information repositories and T1078.004 technique covering valid accounts with elevated privileges. The vulnerability enables attackers to perform reconnaissance and data extraction activities that would typically require higher privileges, effectively allowing them to escalate their access level through the exploitation of this capability check failure. Organizations using the Userback plugin should immediately implement mitigations including plugin updates to versions that address this vulnerability, or implement additional access controls and monitoring to detect unauthorized access attempts. Network segmentation and monitoring of API access patterns can help detect exploitation attempts, while regular security audits of WordPress plugins should include verification of capability checks and access control implementations. The vulnerability serves as a reminder of the critical importance of proper authorization mechanisms in web applications and the potential consequences of overlooking basic security controls in plugin development.