CVE-2026-115277 in User Frontend Plugin
Summary
by MITRE • 10/30/2026
The User Frontend WordPress plugin before 4.3.14 does not sanitise and escape some user-supplied values before reflecting them into HTML attributes in a publicly reachable AJAX response, leading to Reflected Cross-Site Scripting. The affected action is gated by an anonymous nonce that only validates for logged-out requests, so the payload executes against logged-out visitors rather than authenticated users.
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Analysis
by VulDB Data Team • 10/30/2026
The vulnerability identified within the User Frontend WordPress plugin prior to version 4.3.14 represents a classic instance of Reflected Cross-Site Scripting, technically classified under CWE-79 in the Common Weakness Enumeration framework. This flaw stems from an insufficient sanitization and escaping mechanism applied to user-supplied input before it is reflected back into HTML attributes within server-generated responses. The specific technical failure occurs during the processing of AJAX requests where data provided by the client side is directly embedded into the response payload without adequate validation against script injection patterns. When a malicious actor crafts a request containing specially formatted JavaScript code, this code is not stripped or encoded before being returned to the browser, allowing it to execute in the context of the victim's session environment.
The operational impact of this vulnerability is significant because it targets logged-out visitors rather than authenticated users, which expands the potential attack surface considerably. Since the affected AJAX action is gated by an anonymous nonce that validates only for non-authenticated requests, any internet user can trigger the vulnerable code path without needing to log in or possess valid credentials. This accessibility makes the vulnerability particularly dangerous as it allows attackers to target a broad audience of casual site visitors who may have varying levels of security awareness and browser configurations. The execution context is critical here; because the script executes within the domain of the WordPress site, an attacker can potentially access cookies marked with HttpOnly flags if they are not strictly protected against all forms of XSS, or more commonly, perform actions on behalf of the victim such as changing account settings if the user logs in after visiting a malicious link.
From a tactical perspective, this vulnerability aligns with several techniques found in the MITRE ATT&CK framework for enterprise security. Specifically, it falls under T1059 Command and Scripting Interpreter: JavaScript, where attackers use browser-based scripting languages to execute arbitrary code. Furthermore, because the payload is reflected directly from the server response based on input parameters, it also relates to T1189 Drive-by Compromise or potentially T1204 User Execution if combined with social engineering tactics to lure users into clicking malicious links. The lack of proper output encoding means that standard web application firewalls might not always detect these payloads unless they are specifically tuned for XSS patterns involving HTML attribute contexts, highlighting the necessity of defense-in-depth strategies rather than relying solely on perimeter defenses.
To mitigate this vulnerability, immediate action is required to update the User Frontend WordPress plugin to version 4.3.14 or later where the issue has been resolved by implementing robust input validation and output encoding practices. Developers should ensure that all user-supplied data reflected in HTML attributes is strictly escaped using appropriate functions such as esc_attr() in PHP, which converts special characters into their corresponding HTML entities. This prevents the browser from interpreting injected strings as executable code. Additionally, administrators should review server-side logging to identify any potential exploitation attempts prior to patching and consider implementing Content Security Policy headers that restrict script execution sources, thereby adding an extra layer of protection against cross-site scripting attacks even if similar vulnerabilities exist in other plugins or themes on the same domain.