CVE-2021-36875 in uListing Plugin
Summary
by MITRE • 09/28/2021
Authenticated Reflected Cross-Site Scripting (XSS) vulnerability in WordPress uListing plugin (versions
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Analysis
by VulDB Data Team • 07/02/2025
The authenticated reflected cross-site scripting vulnerability identified as CVE-2021-36875 affects the WordPress uListing plugin, representing a critical security flaw that enables attackers with valid user credentials to execute malicious scripts within the context of a victim's browser. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, specifically classified as reflected XSS where malicious input is immediately returned to the user without proper sanitization or encoding. The uListing plugin, designed for property listing and real estate management, fails to adequately validate and sanitize user input parameters before rendering them in web responses, creating an exploitable pathway for attackers to inject malicious JavaScript code.
The technical implementation of this vulnerability occurs when authenticated users interact with the plugin's administrative interfaces or frontend components that process user-supplied data. Attackers can craft malicious payloads that exploit input fields, URL parameters, or form submissions within the plugin's functionality, leading to reflected XSS when the malicious code is executed in the victim's browser context. The vulnerability typically manifests when user input containing script tags or malicious JavaScript is processed by the plugin's backend and subsequently reflected back to the user without appropriate HTML encoding or output sanitization. This flaw allows attackers to bypass standard security measures and execute arbitrary code within the victim's browser session, potentially leading to session hijacking, credential theft, or data manipulation.
The operational impact of this authenticated reflected XSS vulnerability extends beyond simple script execution, as it provides attackers with the capability to perform session manipulation and privilege escalation attacks within the WordPress environment. When an authenticated user accesses a maliciously crafted URL or interacts with compromised plugin functionality, the reflected script executes in their browser, potentially allowing attackers to steal session cookies, modify user interface elements, or redirect users to malicious domains. The authenticated nature of this vulnerability means that attackers need valid user credentials, but once obtained, they can leverage this flaw to execute persistent attacks against other users within the same WordPress installation. This vulnerability directly aligns with ATT&CK technique T1531 for Account Access Removal and T1059.007 for Command and Scripting Interpreter, as it enables attackers to execute malicious scripts and potentially escalate privileges within the WordPress ecosystem.
Mitigation strategies for CVE-2021-36875 require immediate patching of the uListing plugin to the latest version that addresses the reflected XSS vulnerability, typically through proper input validation and output sanitization mechanisms. Organizations should implement comprehensive input validation at multiple layers, including sanitizing all user-supplied data before processing and ensuring proper HTML encoding of output content. Network administrators should consider implementing Content Security Policy (CSP) headers to limit script execution sources and prevent unauthorized code injection. Additionally, regular security audits of WordPress plugins and themes should be conducted to identify similar vulnerabilities, with particular attention to authentication flows and input handling mechanisms. The vulnerability highlights the importance of maintaining up-to-date WordPress installations and plugins, as well as implementing robust security monitoring to detect and respond to potential exploitation attempts. Organizations should also consider implementing web application firewalls to detect and block malicious payloads targeting known XSS patterns, while ensuring that user access controls remain strict and that privileged accounts are protected through multi-factor authentication mechanisms.