CVE-2025-4302 in Stop User Enumeration Plugin
Summary
by MITRE • 07/17/2025
The Stop User Enumeration WordPress plugin before version 1.7.3 blocks REST API /wp-json/wp/v2/users/ requests for non-authorized users. However, this can be bypassed by URL-encoding the API path.
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Analysis
by VulDB Data Team • 01/03/2026
The vulnerability identified as CVE-2025-4302 affects the Stop User Enumeration WordPress plugin, specifically versions prior to 1.7.3, presenting a significant information disclosure risk that undermines the plugin's intended security posture. This flaw represents a classic case of insufficient input validation and access control enforcement within WordPress REST API endpoints. The plugin's primary function is to prevent unauthorized users from enumerating WordPress user accounts through the REST API, which is a critical security measure given that user enumeration can provide attackers with valuable intelligence for targeted attacks including credential stuffing, social engineering, and brute force attempts. The vulnerability manifests when attackers employ URL encoding techniques to bypass the existing access controls, effectively circumventing the plugin's protective mechanisms.
The technical nature of this vulnerability stems from the plugin's incomplete implementation of access control checks within the WordPress REST API framework. While the plugin correctly blocks direct access to the /wp-json/wp/v2/users/ endpoint for unauthorized users, it fails to properly validate and sanitize URL-encoded variations of the same endpoint path. This oversight creates a pathway for attackers to enumerate user information by encoding the API path, which allows the underlying WordPress REST API to process the request despite the plugin's intended restrictions. The vulnerability can be categorized under CWE-284 Access Control Bypass, as it allows unauthorized access to restricted resources through improper access control implementation. Additionally, this issue aligns with ATT&CK technique T1087.001 Account Discovery: Local Account, where attackers seek to enumerate user accounts to establish footholds within systems.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with comprehensive user enumeration capabilities that can significantly aid in subsequent attack phases. When successful, the vulnerability enables threat actors to discover valid usernames, which can then be used for credential spraying attacks against WordPress sites, particularly when combined with other reconnaissance techniques. The ability to enumerate users also facilitates social engineering campaigns and can be leveraged in password spraying or brute force attacks against WordPress installations. This vulnerability is particularly concerning in environments where WordPress is used for content management, as it exposes the underlying user directory to automated enumeration tools and scripts that can systematically harvest user accounts.
Organizations should implement immediate mitigations including updating to the patched version 1.7.3 or later of the Stop User Enumeration plugin, which addresses this bypass mechanism through improved input validation and access control enforcement. Security teams should also consider implementing additional layers of protection such as rate limiting on REST API endpoints, web application firewall rules that detect and block encoded API paths, and monitoring for unusual patterns of user enumeration requests. The mitigation strategy should incorporate principle of least privilege enforcement and comprehensive logging of API access attempts to detect potential exploitation attempts. Furthermore, organizations should conduct security assessments to verify that no other similar bypass mechanisms exist within their WordPress installations, particularly focusing on REST API endpoint access controls and URL encoding validation. This vulnerability serves as a reminder of the importance of thorough input validation and access control implementation in web applications, particularly in the context of API security where seemingly minor implementation flaws can result in significant information disclosure risks.